2. (Project Management: crashing costs) Consider the project described blow and assume that the duration of activities is deterministic rather than random. The crashing costs for all the activities are summarized below. Assume that each activity can be crashed at most twice. a) Determine the ES, EF, LS, LF, and Slack for each activity. b) Determine the critical path c) If the project manager wants to crash the project by 4 weeks, what is the cheapest crashing plan