With respect to PERT and CPM, slack A. is a task or subproject that must be completed. B. marks the start or completion of a task. C. is the amount of time a task may be delayed without changing the overall project completion time. D. is the latest time an activity can be started without delaying the entire project.

The correct answer is C) With respect to PERT and CPM, slack is the amount of time a task may be delayed without changing the overall project completion time.

Explanation:

The CPM (Critical Path Method) method is frequently used in the development and control of projects whose tasks have a fixed duration while the PERT (Program Evaluation and Review Techniques) method is a set of techniques with the same purpose but that allows to work with tasks with estimated probability duration but not deterministic.

Both methods are based on developing a complete scheme that includes all the tasks of a project linked to each other according to their sequence, determining the duration and analyzing different ways of reconfiguring the task planning to optimize the use of the resources of according to the general objectives of the project.

There are tasks that to start performing them must have been completed one or more previous tasks. The overall duration of the project is determined by the Critical Path, which is the sequence of tasks of greater duration. The tasks belonging to the critical path have to be carried out with special care because delays in them would cause delays in the total achievement of the project. That is why these tasks have no slack.

The rest of the tasks have some slack, which is determined by the time that a previous task can be delayed without delaying the total time of completion of the project, that is, not exceeding the duration determined by the critical path.

That is that why we say that the slack is the amount of time a task may be delayed without changing the overall project completion time.