In Agile methodology, who is primarily responsible for prioritizing and managing the backlog?

In Agile methodology, the Product Owner is primarily responsible for prioritizing and managing the backlog. The Product Owner is the key stakeholder who represents the voice of the customer and is responsible for maximizing the value of the product. They work closely with stakeholders to understand requirements, prioritize features, and ensure that the backlog reflects the most valuable items to be worked on by the development team. The Scrum Master facilitates the process, while the development team contributes to refining and estimating backlog items.