To determine how to crash activity times:

A. normal activity costs and costs under maximum crashing must be known.

B. shortest times with crashing must be known.

C. realize that new paths may become critical.

D. All of these are correct.

D. All of these are correct.

Explanation:

It is the method used to reduce the time duration required for a project by spending less time on on the important activities. This will be achieved by committing more resources to the project thus leading to increase in the cost of project.