A newly assigned project manager discovers that input from a business unit critical to project success is missing from project artifacts, and there are many complaints about operational results and alignment affected by that business unit. What should the project manager do?

The project manager should optimize alignment among needs, expectations, and project objectives. This directly addresses the core problem of missing critical input and complaints about operational results and alignment. By focusing on alignment, the project manager can ensure all stakeholders' needs are considered, expectations are managed, and the project's objectives truly reflect what is required for success. Confirming current requirements is a step within optimizing alignment but doesn't encompass the full scope of the problem. Assessing compliance is reactive and doesn't address the root cause of misalignment. Developing a strategy for change responses is premature; the immediate need is to understand and correct the current misalignment before planning for future changes.