The project manager should advise the customer to discuss changes with the product owner, who is responsible for managing the product backlog and prioritizing the user stories. The product owner is the key stakeholder who represents the customer's voice and ensures that the product delivers value to the customer.
The product owner also collaborates with the Scrum team and the Scrum master to plan and execute the sprints. By directing the customer to the product owner, the project manager can avoid confusion and conflict among the team members and maintain the integrity of the Scrum process. The other options are not appropriate because they do not follow the Scrum principles and values. Option B: Document this issue in the sprint backlog for discussion at a team meeting. This option is not correct because the sprint backlog is a list of tasks that the team commits to complete in a sprint, not a place to document issues or changes. The sprint backlog should only be modified by the team members during the sprint, not by the customer or the project manager. Option C: Ask the customer to submit a change request to the project sponsor. This option is not correct because it goes against the agile mindset of welcoming changes and delivering value to the customer.
The project sponsor is not involved in the Scrum process and does not have the authority to approve or reject changes. The product owner is the only person who can accept or reject changes to the product backlog.
Option D: Encourage the team to clarify the requests with the customer. This option is not correct because it may create more confusion and inconsistency among the team members and the customer. The team should not communicate directly with the customer without the involvement of the product owner, who is the single source of truth for the product vision and requirements. The team should focus on delivering the sprint goal and follow the guidance of the product owner and the Scrum master. References: PMBOK Guide 6th Edition, pages 37-38, 170-171, 176-177.