can you solve this question step by step please ?

it is a production manegment course

Consider the following project's information: Activity Immediate Predecessors Optimistic Pessimistic Most Probable 11 8 9 12 D CA B 13 11 14 15 11 15 12 17 17 GBD 16 13 9 1 FH 14 a- Show the PERT/CPM USING ACTIVITY ON ARROW network for this project b- Calculate ES, LS, EF, LF, and Slack for each activity. C- What is the probability to complete the project in the expected completion time plus 4 days later