A project manager is executing two projects at the same time. The critical project's duration must be shortened, but there are insufficient resources and no activities can be overlapped. What should the project manager do?

The project manager should analyze both projects to determine the best use of shared resources. Since the critical project needs its duration shortened and there are insufficient resources, the most practical approach is to reallocate existing resources effectively between the two projects. This involves identifying which resources are critical to each project and optimizing their assignments to prioritize the critical project without jeopardizing the other. Applying resource optimization to justify requesting additional resources is a reactive step that may not be feasible or timely. Providing schedule optimization training is a long-term solution and doesn't address the immediate need. Applying fast-tracking is explicitly ruled out by the constraint that no activities can be overlapped.