please help with the following question

QUESTION 4 JR Construction wants to expand a residential building owned by Pounder Inc. to create more rooms for future tenets. A number of activities must be identified for this project to assist the construction team in organizing and scheduling the project. These activities are listed in the below table. Actual activity times are unknown, so three time estimates have been formulated. (Show evidence of working) Activity Table in Weeks Activities Optimistic time Most Pessimistic Immediate A Likely time time Predecessors M b 3 4 4 7 6 8 A 5 9 B, C B NN D, E a) Calculate the expected activity times for the activities, and variances of each activity. (6 marks) b) i ) Draw a network diagram (AON) of the project activities with activity completion times, ES, EF, LS, and LF times within the activity nodes. (6 marks) ii) What is the expected completion time of the entire project? (1 mark) c) Identify the critical path of the project. (4 marks) d) Calculate the standard deviation of the critical path in the project