What should the project leader suggest?

This situation introduces technical uncertainty. In agile, such scenarios are best addressed by spikes or incremental implementation and early feedback. The PMI Agile Practice Guide (Section 5.2 Spikes and Experimentation) suggests that uncertain work should be prototyped, tested early, and shown during sprint reviews for feedback and learning.

Mike Griffiths in the PMI-ACP Exam Prep Book (Chapter 7: Problem Detection and Resolution) recommends testing high-risk integrations early and iteratively, rather than over-planning.

Option D is correct: developing, testing, and demonstrating early minimizes risk and aligns with agile principles.

Option A leans toward waterfall-style planning and over-documentation.

Option B incorrectly assumes non-functional requirements are less valuable—they’re critical in many systems.

Option C may delay necessary architectural work and increase risk.