In the PMBOK® Guide, the Requirements Traceability Matrix (RTM) is a key output of the Collect Requirements process and a primary tool used during Control Scope. It provides a structure to ensure that every requirement adds business value by linking it to the project objectives.

Why Choice A is correct:

Preventing Scope Creep: Scope creep is the uncontrolled expansion of product or project scope without adjustments to time, cost, and resources.

The " Anchor " Effect: The RTM acts as an anchor. When a new feature is suggested, the Project Manager can check it against the RTM. If the feature doesn ' t map back to an approved business objective or requirement, it is easily identified as " out of scope. "

Maintaining Control: In highly regulated environments like clinical trials, maintaining strict control is essential. The RTM ensures that the team stays focused only on the validated requirements, preventing " gold plating " or undocumented additions.

Analysis of other options:

B (Resource allocation kept to a minimum): The RTM tracks requirements, not people or equipment. While knowing your requirements helps in planning resources, the matrix itself does not minimize or manage the allocation of staff.

C (Project closure will be established): While the RTM is used during closure to verify that all requirements were met, it does not " establish " closure. Closure is a formal process involving the transition of the product and the release of resources.

D (Project costs will be controlled): Cost control is handled through the Cost Management Plan and Earned Value Management. While the RTM helps prevent scope creep (which in turn saves money), its direct function is scope management, not financial tracking.

Key Concept: The Project Management Institute (PMI) emphasizes that the Requirements Traceability Matrix (Choice A) provides the " why " for every task. By ensuring that every work product is tied to a specific requirement, the project manager can maintain a high level of control, ensuring the project delivers exactly what was promised—no more and no less.