A project in execution is affected by a company reorganization and some key team members may leave the project. What should the project manager do next?

The project manager's primary responsibility is to the project's success. The first step when faced with a significant change like potential team member loss due to reorganization is to assess its impact on project objectives, schedule, budget, and quality. This assessment allows the project manager to understand the scope of the problem and then develop appropriate mitigation strategies, referencing the existing project management plan for guidance on risk response and resource management. Discussing the issue with team members (A) is empathetic but doesn't address the project impact first. Looking for replacements immediately (B) is premature without understanding the full impact and potential alternatives. Engaging the sponsor (C) is important, but only after the project manager has analyzed the situation and can present a clear picture of the impact and proposed solutions.