At a project review, a senior manager expresses concern that the project will not meet quality standards. What should the project manager do?

The project manager should go over the quality management plan with the senior manager. This proactive step directly addresses the concern by demonstrating how quality will be managed and controlled throughout the project. The quality management plan outlines the quality standards, metrics, processes, and responsibilities, providing a clear and documented approach to ensuring quality. Requesting UAT plan approval is premature and doesn't address the underlying concern about meeting standards. Simply stating that approved standards exist doesn't provide reassurance or detail. Estimating backlog items is a development activity, not a direct response to a senior manager's quality concern.