According to the PMBOK® Guide and the PMI Standard for Business Analysis, the Business Case is a critical project document created during the pre-initiation phase. It justifies the investment by outlining the business need and the proposed solution ' s value.

Why Choice C is correct: A Feasibility Study is an essential component of (or precursor to) a Business Case. It evaluates the technical, economic, legal, operational, and schedule viability of the proposed solution. If stakeholders view the project as " inefficient, " it indicates that the proposed solution has not been adequately vetted for operational efficiency or practical implementation. Without a feasibility study, there is no documented evidence that the " ambitious " goals can be met using a streamlined or effective approach, leading to stakeholder skepticism.

Analysis of other options:

A (WBS): The Work Breakdown Structure is a detailed planning document created much later in the Scope Management process. It is not part of a Business Case.

B (Approval from stakeholders): While the Business Case requires approval to move to the Project Charter, " approval " itself is the result of a good business case, not a missing component that explains why the work seems inefficient.

D (Root cause analysis): While root cause analysis helps identify the problem, the stakeholders ' concern here is specifically about the efficiency of the work/solution being proposed. A feasibility study directly addresses whether the chosen solution is the most efficient way to achieve the desired outcome.

The Business Case should bridge the gap between a high-level vision (ambition) and practical execution. When stakeholders doubt the efficiency of the work, the Project Manager must look back at the feasibility study to ensure the most effective alternative was selected and communicated.