Regression testing is a type of testing that verifies that previously tested software still performs correctly after changes. Regression testing can help prevent re-opening of defects fixed earlier by ensuring that they do not cause any new failures or side effects. The first recommendation to the company is to verify existing regression test suite are adequate, and augment it, if required, in order to ensure that defects fixed earlier get re-tested in each subsequent build. This can help improve the coverage and effectiveness of regression testing and detect any regression defects as soon as possible. Automating existing test suites may also help reduce the time and effort required for regression testing, but this is not the first recommendation, as automation may not be feasible or cost-effective for all test cases. Analyzing the product modules containing maximum defects and getting them thoroughly tested and defects fixed as a one-time activity may also help reduce the defect density and improve the quality of those modules, but this is not the first recommendation, as it does not address the root cause of re-opening defects fixed earlier. Training or replacing the teams responsible for development and testing of the modules containing maximum number of defects may also help improve their skills or performance, but this is not the first recommendation, as it may not be necessary or appropriate for all teams.
Verified References: [A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer], Chapter 2, page 19; Chapter 4, page 45.

The correct answer can be derived by applying the given rules to each case:
A is ST certified and has 12 years of testing experience, which is more than 10 years. Therefore, A does not match any of the rules and the result is unknown.
B is not ST certified and has 7 years of testing experience, which is between 5 and 10 years. Therefore, B matches rule 3 and the result is limited access.
C is not ST certified and has 3 years of testing experience, which is less than 5 years. Therefore, C does not match any of the rules and the result is unknown. Verified Reference: This question does not require any external references, as it is based on logical reasoning.

System testing is a level of testing performed to evaluate the behavior and quality of a whole software product or system. System testing can include various types of testing, such as:
* I) Usability testing: A type of testing that evaluates how easy, efficient and satisfying it is to use the software product or system from the user's perspective.
* II) Requirements based scenarios testing: A type of testing that verifies that the software product or system meets its specified requirements or user stories by executing realistic scenarios or workflows.
System testing does not include the following types of testing, as they are more suitable for lower levels of testing, such as unit testing or integration testing:
* III) Testing parts of the code in isolation: A type of testing that verifies the functionality and quality of individual software components or units by isolating them from other components or units.
* IV) Correct order of parameters in API calls: A type of testing that verifies the functionality and quality of software components or units that communicate with each other through application programming interfaces (APIs) by checking the correct order and format of parameters in API calls. Verified References: [A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer], Chapter 2, page 20-21; Chapter 4, page 34-35.

Exploratory testing is an approach to testing that emphasizes learning, test design and test execution at the same time. Exploratory testing relies on the tester's skills, creativity and intuition to explore the software under test and discover defects. Exploratory testing is suitable for a new project with little documentation and high probability for bugs, as it can help uncover unknown requirements, assumptions and risks. Exploratory testing is not requirements based testing, which is an approach to testing that derives test cases from documented requirements or specifications. Requirements based testing is not feasible for a new project with little documentation, as it requires clear and complete requirements to be available. Exploratory testing is not metric based approach, which is an approach to testing that uses quantitative measures to monitor and control the testing process and evaluate the quality of the software product. Metric based approach is not effective for a new project with high probability for bugs, as it may not capture all aspects of quality and may lead to false confidence or unrealistic expectations. Exploratory testing is not regression testing, which is an approach to testing that verifies that previously tested software still performs correctly after changes. Regression testing is not relevant for a new project with no previous versions or baselines. Verified References: [A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer], Chapter 5, page 47-48.

Component testing (also known as unit testing or module testing) is a level of testing that focuses on verifying the functionality and quality of individual software components (such as modules, classes, functions, methods, etc.). Component testing mainly tests interfaces and interaction between components, as well as internal logic and data structures of the components. Component testing may be applied using a test-first approach (such as test-driven development or behavior-driven development), where tests are written before the code is implemented. Component testing does not identify defects in modules and classes, as this is a result of component testing, not an objective. Simulators and stubs may be required for component testing, as they can simulate or replace missing or incomplete components or external systems that are needed for testing. Verified Reference: A Study Guide to the ISTQB Foundation Level 2018 Syllabus - Springer, page 19.