The product owner is a key stakeholder in an agile project, who is responsible for defining and prioritizing the product backlog, providing feedback and acceptance for each product increment, and maximizing the value of the product and the work of the development team1. The product owner is not expected to focus on the cost or budget of the project, but rather on the value and quality of the product. The project manager should have worked with the product owner to clarify their role and expectations, and to explain the purpose and scope of the agile ceremonies, such as sprint planning, daily stand-up, sprint review, and sprint retrospective2. These ceremonies are meant to facilitate collaboration, communication, and adaptation among the project team and the product owner, not to report on the budget or cost of the project. The other options are not relevant or effective in changing the product owner's behavior. References: 1: PMI, A Guide to the Project Management Body of Knowledge (PMBOKGuide) - Seventh Edition, Project Management Institute Inc., 2021, p. 177. 2:
PMI, Agile Practice Guide, Project Management Institute Inc., 2017, pp. 50-53.