4. Finally, solve the following problem. Although not covered in class, the relationship between direct and indirect costs is described in your book. The question requires you find the lowest total cost (the sum of indirect and direct costs). Activity Normal Time Crash Normal Time Cost Crash Cost Immed. Pred. A 2. 1 $50 $70 B 4 2 80 160 A C 8 4 70 110 A D 6 5 60 80 . E 7 6 100 130 G B, C D 4 3 40 100 5 01 4 100 150 E, F a. Construct the network diagram. b. Indicate the critical path when normal activity times are used. c. Compute the minimum total direct cost for each project duration based on the cost associated with each activity. Consider durations of 17, 18, 19, 20, 21, and 22 weeks. d. If the indirect costs for each project duration are $800 at 22 weeks and then decline by $100 per week for each week shortened (until the indirect cost is $0), what is the total project cost for each duration. Indicate the minimum total project cost and its duration