According to the PMI Guide to Business Analysis, a requirements traceability matrix is a tool that helps to ensure that the requirements are aligned with the business needs and objectives, and that they are verified and validated throughout the project life cycle. A requirements traceability matrix can also help to identify gaps, redundancies, and inconsistencies in the requirements. If the requirements matrix did not adequately track back to client requirements, it could result in a product that does not meet the client's expectations or specifications, even if it passes the test plan. Therefore, it is important to establish and maintain a clear and accurate traceability of requirements from their source to their implementation and verification. References:
PMI Guide to Business Analysis, page 179-180.

The business analyst should use a traceability matrix to help communicate the status of the requirements. A traceability matrix is a document that shows the relationships and dependencies among the requirements, and tracks their changes, verification, and validation throughout the project life cycle. A traceability matrix can help the business analyst and the project manager to monitor the progress and quality of the requirements, and to identify any gaps, issues, or risks. References: PMI Professional in Business Analysis (PMI-PBA) Examination Content Outline1, page 20; Business Analysis for Practitioners: A Practice Guide2, page 100.

Workshop sessions are a technique to elicit, analyze, and prioritize requirements by bringing together a group of stakeholders, such as subject matter experts, to collaborate and reach a consensus. Workshop sessions can be used to identify and prioritize the requirements for a newly approved project. The other techniques are not suitable for this purpose. Delphi technique is a technique to obtain expert opinions anonymously and iteratively until a consensus is reached. Brainstorming is a technique to generate a large number of ideas or solutions in a short time. Idea and mind mapping is a technique to visually organize ideas or information using diagrams or graphs. References: PMI-PBAExamination Content Outline, page 10; PMI-PBA Reference List, page 1, BABOK Guide v3, page 50.

A questionnaire is an elicitation technique that involves sending a set of written questions to a large number of users or stakeholders to gather information about their needs, preferences, opinions, or feedback. A questionnaire is best suited for eliciting information from a large group of users in a short period of time, as it is cost-effective, easy to administer, and allows for anonymity and standardization. A questionnaire can also reach users who are geographically dispersed or unavailable for face-to-face meetings. References: PMI Guide to Business Analysis, Chapter 6, Section 6.3.2.9; PMI Professional in Business Analysis (PMI-PBA) Examination Content Outline, Domain III: Analysis, Task 2.

According to the PMI Professional in Business Analysis objectives and content, a vision/scope document is a document that describes the high-level vision, scope, and objectives of a project or initiative. It also defines the key stakeholders, business needs, expected benefits, assumptions, constraints, and risks. A vision/scope document can help to align the stakeholders' views of organizational improvement with the project's purpose and direction. It can also help to establish a common understanding and agreement among the stakeholders, and provide a basis for planning and prioritizing the requirements. References:
* PMI Professional in Business Analysis objectives and content: PMI-PBA Certification
* PMI Professional in Business Analysis reference list: PBA Reference List
* PMI Professional in Business Analysis study guide: Study.com