An agile project manager would like to convert the requirements document into epics, capabilities, features and stories in order to create a product backlog that can be prioritized and refined by the agile team and the product owner. The product backlog is a dynamic and evolving artifact that represents the customer's needs and expectations for the product. To estimate the story duration, the agile project manager should use the team's historical data and empirical evidence from previous iterations. The agile project manager should also involve the team members who will perform the work in the estimation process, as they have the best knowledge and expertise about the tasks and the complexity involved. The agile project manager should estimate the story duration in one iteration, as this is the timebox for delivering a potentially releasable product increment. Estimating the story duration in one iteration allows the agile project manager to plan and monitor the iteration progress, adjust the scope and priorities based on feedback and changes, and ensure that the team delivers value to the customer in a timely manner. Estimating the story duration in more than one iteration would introduce uncertainty and risk, as the team's velocity, the customer's requirements, and the product's quality might change over time. Estimating the story duration in less than one iteration would not be feasible, as the team would not have enough time to complete the work and validate the results. References: PMBOK Guide, 6th edition, Section 6.2, 6.3, 6.4, 6.5, Agile Practice Guide, Section 3.2,
3.3, 4.2, 4.3