A simple CPM network has three activities, D, E, and F. D is an immediate predecessor of E and of F. E is an immediate predecessor of F. The activity durations are D=4. E=3. F=6. The critical path is D-E-F. duration 12. B) The critical path is D-F, duration 10. C) Slack at Dis 0 periods. D) Slack at E is 3 periods. E) Both A and C are true.