A project manager is trying to explain to a stakeholder why projects are progressively elaborated upon. Which of the following is the BEST explanation?

At project initiation, requirements, constraints, and risks are not fully known, creating a degree of uncertainty that makes complete upfront planning impossible. Progressive elaboration addresses this by allowing the project team to incrementally develop and refine plans - such as rolling wave planning - as clarity is gained through the project lifecycle, reducing uncertainty over time.

Start and finish dates are scheduling outputs established during planning and do not represent the type of iterative uncertainty that progressive elaboration is specifically designed to address.

Being part of a program requiring coordination describes a governance relationship between related projects, which is a separate concept from the need to iteratively develop project details.

Projects typically begin with high-level and limited inputs, not detailed ones - progressive elaboration exists precisely because initial inputs lack sufficient detail, not to explain detail that already exists.