a) Which activity(s) should be crashed and what is the cost to reduce the project completion time from 22 to 21 days? b) Which activity(s) should be crashed and what is the cost to reduce the project completion time from 21 to 20 days? c) Which activity(s) should be crashed and what is the cost to reduce the project completion time from 20 to19 days? d) What is the total cost to reduce the project from the original normal completion time to 19 days