A multiyear, resource-constrained project is mid-execution. In a progress meeting a potential schedule delay is identified, although the team is working hard and many deliverables are complete. What should the project manager do immediately?

The project manager's immediate action should be to understand the extent and cause of the potential delay. Asking the project planner to identify the critical path and delayed activities will pinpoint where the schedule is truly impacted. Investigating the reasons for the delay is crucial for developing an effective solution, rather than reacting prematurely. Registering the risk and presenting new resource requirements (A) is premature without understanding the root cause and impact. Preparing a monthly report (B) is a reporting function, not an immediate problem-solving step. Updating the schedule with WIP (D) is part of routine tracking but doesn't address the cause of the potential delay or provide a path forward.