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 durations are A = 4, B = 3, C = 5. A. The critical path is A-B-C, duration 12. B. The critical path cannot be determined without knowing PERT expected activity times. C. The critical path is A-C, duration 10.5 D. The network has no critical path. E. The critical path is A-B-C, duration 9