A simple CPM network has three activities, A, B, and C. A is an immediate predecessor of B and of C. B is an immediate predecessor of C. The activity duration's are A=4, B=3, C=8)

What is the critical path?

A. The critical path is A-B-C, duration 15.

B. The critical path cannot be determined without knowing PERT expected activity times.

C. The critical path is A-C, duration 12.

D. The critical path is A-B-C, duration 13.5

E. The network has no critical path.