The project manager should review the resources required for the tasks on the critical path because these are the tasks that determine the project duration and have the highest risk of causing delays. By reviewing the resources, the project manager can identify any resource shortages, conflicts, or overallocation, and take corrective actions to optimize the resource utilization and avoid penalties. The other options are not the best choices because they do not directly address the root cause of the delay, which is the resource allocation. Discussing the issue with the project sponsor (option A) may help to escalate the problem, but it does not solve it. Reviewing and updating the risk management plan (option C) may help to identify and mitigate any potential risks, but it does not address the current situation. Allocating resources to develop the competencies of the other team members (option D) may help to improve the team performance in the long run, but it does not help to complete the critical project on time. References: PMBOK Guide, 6th edition, pages 215-216, 258-259, 333-334. How To Find The Correct Answer On PMP Exam Questions. Free PMP Questions and Answers – Are You Ready for PMP Exam?.