During a system demo a stakeholder rejects the features completed from recent user stories, claiming the product fails to meet regulatory quality standards. What should the project manager have done to prevent this?

The correct answer is to review with the product owner that all acceptance criteria were met for the stories worked on in the iteration. Acceptance criteria define the conditions that must be satisfied for a user story to be considered complete and acceptable. These criteria often include regulatory requirements, quality standards, and stakeholder expectations. Ensuring they are met before a demo would prevent such rejections. The other options are less effective: Ensuring the project sponsor understood the project scope is important but doesn't directly address the quality and regulatory compliance of specific features. Ensuring stakeholder concerns were properly addressed within the iteration is too vague; the mechanism for addressing them is through acceptance criteria. Reviewing that all stories were in the project backlog only confirms they were planned, not that they were completed to the required quality or regulatory standards.