This answer is correct because shift-left in testing is an approach that aims to perform testing activities as early as possible in the software development lifecycle, in order to find and fix defects faster and cheaper, and to improve the quality of the software product. Continuous integration is a practice that supports shift-left in testing, as it involves integrating and testing the software components frequently, usually several times a day, using automated tools and processes. Continuous integration can reduce the time between the introduction of a defect and its detection, thereby reducing the cost to fix it and the risk of accumulating defects that could affect the functionality or performance of the software product. Reference: ISTQB Foundation Level Syllabus v4.0, Section 3.1.1.3, Section 3.2.1.3

Explanation
The minimum number of test cases needed to cover the full decision table associated with this scenario is 6.
This is because the decision table has 4 conditions (type of customer and amount of sale) and 4 actions (bonus percentage). The conditions have 2 possible values each (Basic or Premium, and G1, G2 or G3), so the total number of combinations is 2 x 2 x 2 x 2 = 16. However, not all combinations are valid, as some of them are contradictory or impossible. For example, a sale cannot be both less than 300 euros and greater than 2000 euros at the same time. Therefore, we need to eliminate the invalid combinations and keep only the valid ones.
The valid combinations are:
Type of customer
Amount of sale
Bonus percentage
Basic
G1
3%
Basic
G2
5%
Basic
G3
7%
Premium
G1
5%
Premium
G2
7%
Premium
G3
10%
These 6 combinations cover all the possible values of the conditions and actions, and they are the minimum number of test cases needed to cover the full decision table.
References: ISTQB Certified Tester Foundation Level (CTFL) v4.0 sources and documents,

Traceability is the ability to trace the relationships between the items of the test basis, such as the requirements, the design, the risks, etc., and the test artifacts, such as the test cases, the test results, the defects, etc. Traceability can provide various benefits for the testing process, such as improving the test coverage, the test quality, the test efficiency, and the test communication. However, not all the statements given are true about the value of maintaining traceability between the test basis and test work products. The statement that is not true is option C, which says that test objectives should be the same for all test levels, although the number of tests designed at various levels can vary significantly. This statement is false, because test objectives are the goals or the purposes of testing, which can vary depending on the test level, the test type, the test technique, the test environment, the test stakeholder, etc. Test objectives can be defined in terms of the test basis, the test coverage, the test quality, the test risk, the test cost, the test time, etc. Test objectives should be specific, measurable, achievable, relevant, and time-bound, and they should be aligned with the project objectives and the quality characteristics. Test objectives should not be the same for all test levels, as different test levels have different focuses, scopes, and perspectives of testing, such as component testing, integration testing, system testing, and acceptance testing. The other statements are true about the value of maintaining traceability between the test basis and test work products, such as:
Traceability can be useful for assessing the impact of a change to a test basis item on the corresponding tests: This statement is true, because traceability can help to identify which tests are affected by a change in the test basis, such as a new requirement, a modified design, a revised risk, etc., and to determine the necessary actions to update, re-execute, or re-evaluate the tests. Traceability can also help to estimate the effort, the cost, and the time needed to implement the change and to verify its impact on the software system.
Traceability can be useful for determining how many test basis items are covered by the corresponding tests: This statement is true, because traceability can help to measure the test coverage, which is the degree to which the test basis is exercised by the test cases. Traceability can help to identify which test basis items are covered, partially covered, or not covered by the tests, and to evaluate the adequacy, the completeness, and the effectiveness of the testing process. Traceability can also help to identify the gaps, the overlaps, or the redundancies in the test coverage, and to prioritize, optimize, or improve the test cases.
Traceability can be useful to support the needs required by the auditing of testing: This statement is true, because traceability can help to provide evidence, documentation, and justification for the testing activities, results, and outcomes. Traceability can help to demonstrate that the testing process follows the standards, the regulations, the policies, and the best practices that are applicable to the software system, the project, or the organization. Traceability can also help to verify that the testing process meets the expectations, the needs, and the satisfaction of the users and the stakeholders. Reference: ISTQB Certified Tester Foundation Level (CTFL) v4.0 sources and documents:
ISTQB® Certified Tester Foundation Level Syllabus v4.0, Chapter 1.2.2, Testing Policies, Strategies, and Test Approaches1 ISTQB® Certified Tester Foundation Level Syllabus v4.0, Chapter 2.1.1, Test Planning1 ISTQB® Certified Tester Foundation Level Syllabus v4.0, Chapter 2.1.2, Test Monitoring and Control1 ISTQB® Certified Tester Foundation Level Syllabus v4.0, Chapter 2.1.3, Test Analysis and Design1 ISTQB® Glossary of Testing Terms v4.0, Traceability, Test Basis, Test Artifact, Test Objective, Test Level, Test Coverage, Test Quality, Test Risk, Test Cost, Test Time2

Test exit criteria are the conditions that must be fulfilled before concluding a particular testing phase. These criteria act as a checkpoint to assess whether we have achieved the testing objectives and are done with testing1. Test exit criteria are typically defined in the test plan document, which is one of the outputs of the test planning phase. The test plan document describes the scope, approach, resources, and schedule of the testing activities. It also identifies the test items, the features to be tested, the testing tasks, the risks, and the test deliverables2. According to the ISTQB Certified Tester Foundation Level Syllabus v4.0, the test plan document should include the following information related to the test exit criteria3:
* The criteria for evaluating test completion, such as the percentage of test cases executed, the percentage of test coverage achieved, the number and severity of defects found and fixed, the quality and reliability of the software product, and the stakeholder satisfaction.
* The criteria for evaluating test process improvement, such as the adherence to the test strategy, the efficiency and effectiveness of the testing activities, the lessons learned and best practices identified, and the recommendations for future improvements.
Therefore, the test plan document is the most appropriate test document to find the test exit criteria described.
The other options, such as test design specification, project plan, and requirements specification, are not directly related to the test exit criteria. The test design specification describes the test cases and test procedures for a specific test level or test type3. The project plan describes the overall objectives, scope, assumptions, risks, and deliverables of the software project4. The requirements specification describes the functional and non-functional requirements of the software product5. None of these documents specify the conditions for ending the testing process or evaluating the testing outcomes. References = ISTQB Certified Tester Foundation Level Syllabus v4.0, Entry and Exit Criteria in Software Testing | Baeldung on Computer Science, Entry And Exit Criteria In Software Testing - Rishabh Software, Entry and Exit Criteria in Software Testing Life Cycle - STLC [2022 Updated] - Testsigma Blog, ISTQB releases Certified Tester Foundation Level v4.0 (CTFL).

Independence in testing provides several benefits. Firstly, it helps remove the biases that might be introduced by the person who developed the code or created the tests (ii). This is because an independent tester can evaluate the software without being influenced by their prior work. Secondly, different people bring different perspectives and assumptions to the testing process, which can help uncover different types of weaknesses (iv).
References:
* ISTQB CTFL Syllabus V4.0, Section 1.5.3 on the benefits of independence in testing, which emphasizes the reduction of bias and the introduction of diverse viewpoints.