CAPM Practice: Demonstrate an understanding of a project management plan schedule

A summary activity (hammock or summary bar in Gantt charts) spans multiple subordinate activities, showing their collective start and end dates as a single bar. In WBS-based schedules, they represent work packages or phases, with the summary bar spanning from the earliest start to the latest finish of all activities within the group.

**Why not B:** An activity that must be completed before the project can begin describes a predecessor or prerequisite, not a summary activity. Summary activities aggregate groups of subordinate activities rather than serving as preconditions.

**Why not C:** A critical path activity with the longest duration describes a specific scheduling characteristic, not the concept of a summary activity. Summary activities span their child activities regardless of whether those activities are on the critical path.

**Why not D:** An activity performed by a resource working across multiple projects describes a shared resource situation, not a summary activity. Summary activities are a scheduling construct that groups related work, unrelated to how resources are allocated.