What is the purpose of the Business Case practice?
This is the core purpose of the Business Case practice.
Why this answer
The Business Case practice in PRINCE2 provides a mechanism to judge whether the project is desirable (benefits outweigh costs), viable (achievable within constraints), and achievable (feasible with available resources). It is the central justification for initiating and continuing the project, ensuring ongoing business justification throughout the project lifecycle.
Exam trap
PeopleCert often tests the distinction between the Business Case practice (which justifies the project) and the Plans practice (which defines how the project will be executed), leading candidates to confuse scope definition with business justification.
How to eliminate wrong answers
Option A is wrong because defining the project's scope and deliverables is the purpose of the Product Description and Project Plan, not the Business Case practice. Option C is wrong because monitoring and controlling project progress is the role of the Progress practice, which uses tolerances and reporting. Option D is wrong because assigning roles and responsibilities is the function of the Organization practice, which defines the project management team structure.