In the Collect Requirements process of the PMBOK® Guide, selecting the right elicitation technique depends on the nature of the requirement. Cross-functional requirements are those that impact multiple departments, systems, or stakeholders simultaneously (e.g., a security feature that affects IT, Legal, and end-users).

Why Choice C is correct: Facilitated Workshops (also known as Joint Application Design/Development or JAD sessions) are specifically designed to bring together key cross-functional stakeholders.

Consensus Building: Because cross-functional requirements often involve conflicting needs from different departments, a workshop allows for real-time negotiation and resolution.

Efficiency: Instead of conducting separate interviews, the Business Analyst can get all relevant parties in one room (or virtual space) to define the requirement collectively.

Discovery: Interdependencies between departments often surface during the dialogue that happens in a workshop setting, which might be missed in isolated sessions.

Analysis of other options:

A (Focus groups): These bring together prequalified stakeholders and subject matter experts to learn about their expectations and attitudes about a proposed product. While useful, they are more about " sentiment " than the rigorous technical and functional negotiation required for cross-functional alignment.

B (Prototyping): This is a method of obtaining early feedback on requirements by providing a working model. It is a " validation " tool rather than an initial elicitation method for complex, multi-departmental logic.

D (Interviews): Interviews are excellent for deep dives with a single stakeholder. However, they are notoriously poor for cross-functional requirements because the interviewer hears only one perspective at a time, making it difficult to spot contradictions between departments until much later.

Key Concept: The Project Management Institute (PMI) identifies facilitated workshops as a primary tool for developing a shared understanding. When requirements " cross lines " on an organizational chart, the collaborative environment of a workshop (Choice C) is the most effective way to ensure the requirement is complete, accurate, and agreed upon by all parties.