please answer the question and give an explanation:

4. Consider the project below (the times are in days): a) Construct a network diagram. (1 point) b) Calculate the expected time and variances for all the activities. (2 points) c) Identify all the paths (including path durations and path variances) and find the critical path (1 point) d) How sure are you about completing the project within 22 days? (2 points)