The correct answer is D - Discuss the issue with the team at the next project retrospective. Fatigue and declining productivity are ideal topics for the sprint retrospective. Retrospectives provide a dedicated time for the team to reflect on what's working and what's not, and they promote continuous improvement in a psychologically safe environment. PMI Agile Practice Guide: "Retrospectives allow teams to reflect on how they work and to continuously improve their practices, processes, and team dynamics." (PMI Agile Practice Guide, Section 5.8 - Retrospectives) Mike Griffiths: "Retrospectives are opportunities to openly discuss issues such as burnout or fatigue and decide as a team what improvements to implement." (PMI-ACP Exam Prep, Chapter 7 - Continuous Improvement) Incorrect options: * A (daily standup) is focused on immediate blockers, not deep reflection. * B might help but creates unnecessary ceremony; the retrospective is the correct venue. * C escalates the issue outside the team prematurely.