Which of these statements regarding time-cost tradeoffs in cpm networks is true?
a. crashing shortens the project duration by assigning more resources to one or more of the critical tasks.
b. crashing is not possible unless there are multiple critical paths.
c. crashing a project often reduces the length of long-duration, but noncritical, activities.
d. the crash time always exceeds the normal time.
e. activities not on the critical path can never be on the critical path, even after crashing.