The PMO has started implementing iterative tools. A project manager sees an opportunity to use these tools on a new project, but stakeholders disagree about adopting the adaptive tool. What should the project manager do first?

The project manager's first step should be to understand the root cause of the disagreement. Investigating the reasons allows the project manager to identify specific concerns, misconceptions, or conflicting interests among stakeholders. This understanding is crucial for finding common ground and building consensus, which is essential for successful project execution. Scheduling training (B) prematurely assumes the disagreement stems from a lack of understanding, which may not be the case. Discussing other tools (C) might be a later step, but without understanding the current objections, it's unlikely to resolve the core issue. Updating the risk register and escalating (A) are actions that might follow if consensus cannot be reached, but they are not the initial step to resolve the disagreement itself.