please help with the following question

QUESTION 4 Devon Construction wants to expand an apartment building owned by Alleyne Inc. to create more apartment 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 uncertain, so three time estimates have been formulated. Activity Table in Weeks Activities Optimistic Most Pessimistic Immediate time Likely time time Predecessors a m b A 2 B 3 5 - C 4 6 8 A D 2 3 5 B. C E 2 4 5 B D Calculate the expected activity times for the activities, as well as their standard deviations [square root of variance] (6 marks) b) 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) C) What is the expected completion time of the entire project? (1 mark) d) Identify the critical path which is the path that comprises the activities with zero slack. Show evidence of working. (2 marks)