Anetwork consists of the following list. Times are given in weeks. Activity Preceding Optimistic Probable Pessimistic A 5 11 14 3 3 6. 6. 10 14 D A, B 3 7. E B 4 11 F 13 D. E 4 6 H F 3 3 9 a) Draw the network diagram. b) Calculate the expected duration and variance of each activity. c) Calculate the expected duration and variance of the critical path. d) Calculate the probability that the project will be completed in less than 28 weeks.