CAPM Practice: Demonstrate an understanding of project management planning

A milestone is a significant point or event in the project that marks completion of a major deliverable or phase. It has zero duration—it's a point in time, not a period. Task duration, on the other hand, represents the amount of time required to complete a specific activity and is expressed in time units (hours, days, weeks). This is a fundamental distinction in project scheduling.

**Why not A:** Milestones are not measured in weeks, and task durations are not limited to days or hours. The key distinction is that a milestone has zero duration (it is a point in time), while task duration can be expressed in any time unit. The units of measurement are not what differentiates them.

**Why not C:** Milestones do not always require stakeholder approval. While some milestones may trigger approval gates, this is not a defining characteristic. The fundamental distinction is that milestones are zero-duration markers, while task durations represent actual work time.

**Why not D:** Milestones can occur at any point in a project, not only at the end of a phase. They can mark the start of a phase, completion of a key deliverable, or any other significant event. The restriction to phase endings is incorrect and overly limiting.