According to the PBA Guide, the product owner is the person who is responsible for defining and prioritizing the product backlog, which contains the requirements for the project. The product owner also provides feedback and acceptance for the deliverables produced by the development team. Therefore, the project manager should work with the product owner to clarify the requirement and the acceptance criteria for the task, as they are the best source of information and authority for the project scope. This is also consistent with the agile principles of collaboration, customer satisfaction, and responding to change. References:
* PBA Guide, Chapter 2, Section 2.3.1, Roles and Responsibilities of the Product Owner
* PBA Guide, Chapter 3, Section 3.2.1, Product Backlog
* PBA Guide, Chapter 4, Section 4.3.2, Feedback and Acceptance
* PMBOK Guide, Chapter 13, Section 13.2.2.1, Agile/Adaptive Environments
* PMBOK Guide, Appendix X3, Section X3.2, Agile Principles