What is the purpose of a dummy activity in a network?

A dummy activity in a network diagram serves a crucial purpose in project management by maintaining the logical structure of the network without introducing any additional time or resources. This is particularly important in scheduling because it helps show dependencies between tasks that may not require a duration of their own.

For example, when two or more tasks must be completed before another task can start, a dummy activity can be used to illustrate this relationship clearly. It creates a visual representation of the sequence of tasks while ensuring that the flow of the project is logical and does not result in any loops or cycles. By using a dummy activity, project managers can effectively communicate the necessary order of operations without making the network more complicated or inflating the project’s timeline.

In contrast, the other choices do not accurately describe the function of a dummy activity. Representing a task with a specific duration would imply that it requires time and resources, which is not the case for dummy activities. Similarly, simply adding more edges to a network doesn't capture the essential purpose of maintaining clarity in task dependencies, and increasing the total time of the project contradicts the very nature of what a dummy activity is intended to do.