Crash time is defined as

a. the shortest possible time to complete an activity.

b. the time necessary to complete an activity under abnormal conditions.

c. the difference between earliest start time and earliest finish time.

d. the activity time associated with any management intervention.

a. the shortest possible time to complete an activity. Crash Time is the shortest possible time it takes to complete a job or activity by expediting everything associated with the job or activity. It's a good example of the time/money trade off in that you can frequently decrease the time something takes by spending more money. So let's look at the choices and see why they're right or wrong. a. The shortest possible time to complete an activity. * This pretty much is the same as the definition, so it's the correct choice. b. The time necessary to complete an activity under abnormal conditions. * This answer raises the question "What's an abnormal condition?" Does everything go right and things go faster? Does everything go wrong and it's gonna take a long time? In my experience both extremes are "abnormal". So this is a wrong choice. c. The difference between earliest start time and earliest finish time. * This answer is lacking the idea of a job or task. Earliest start time of what? So it's a wrong choice. d. The activity time associated with any management intervention. * So a phone call from management would be crash time? The boss walking past to see how things are doing? This is a very open ended and ambiguous answer. So it's wrong.