At a retrospective the project manager hears stakeholders repeatedly complain during iteration demos that product features are not delivered as requested. What should the project manager advise the Product Owner to ensure features are delivered as requested?

The correct answer is validating acceptance criteria with stakeholders before backlog refinement. This ensures that the Product Owner and development team clearly understand stakeholder expectations for each feature before development begins. By involving stakeholders in defining these criteria, the team builds the right product from the start, addressing the complaint of features not being delivered as requested. Including stakeholders in daily standups (A) is generally not recommended as standups are for the development team to synchronize, not for stakeholder updates. Avoiding stakeholders in iteration reviews (C) is counterproductive; reviews are crucial for feedback and transparency. Creating a requirements traceability matrix (D) is a good practice for managing requirements, but it doesn't directly address the root cause of features not meeting expectations as effectively as upfront validation of acceptance criteria.