7. 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 = 8.

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

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

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

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

E) The network has no critical path.

8. A simple CPM network has five activities, A, B, C, D, and E. A is an immediate predecessor of C and of D. B is also an immediate predecessor of C and of D. C and D are both immediate predecessors of E.

A) There are two paths in this network.

B) There are four paths in this network.

C) There are five paths in this network.

D) There are 25 paths through this network.

E) There is no critical path in this network.

please explain both answers

thanks