Economic saving of time results by crashing A. Cheapest critical activity B. Cheapest noncritical activity C. Costliest critical activity D. Costliest noncritical activity

The correct answer is: A. Cheapest critical activity.

Crashing is a technique used in project management to shorten the project schedule by adding resources to critical activities. Critical activities are those that have no slack, so any delay in them will delay the entire project. The cheapest critical activity is the activity that can be shortened the most at the lowest cost.

The other options are incorrect because:

• Option B, cheapest noncritical activity, is incorrect because noncritical activities have slack, so they can be delayed without delaying the entire project. Therefore, there is no need to crash them.
• Option C, costliest critical activity, is incorrect because crashing a critical activity will always increase the cost of the project.
• Option D, costliest noncritical activity, is incorrect because crashing a noncritical activity will not always save time.