Which of the following elements would be needed to prepare an effective project scope document?

An approved project milestone schedule is developed as part of detailed project planning, which occurs after the project scope has been defined, not as an input to scope definition.

An approved risk assessment document is a result of risk management planning, which relies on an already defined project scope to identify and assess risks, so it's not an input to scope definition.

An approved project charter is a critical input for preparing the project scope document because it formally authorizes the project and provides the high-level project objectives, deliverables, and scope from which the detailed scope is then elaborated. Without the charter, the project lacks formal authority and initial direction.

A responsibility assignment matrix is a detailed planning output that allocates roles and responsibilities to activities, which are identified after the project scope has been clearly established.