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 $13\mathrm{.}5$

B$.$

The network has no critical path

C$.$

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

D$.$

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

E$.$

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