Please answer C,D,E

1. When an accounting firm audits a corporation, the first phase of the audit involves obtaining "knowledge of the business. This phase of the audit requires the activities in Table 1. Table 1 Activity Description Predecessors Duration Days) A Determining terms of engagement 3 B Appraisal of audit ability risk and materiality A 10 Identification of types of transactions and A 14 possible errors D Systems description B,C E Verification of systems description D F Evaluation of internal controls E G Design of audit approach E The duration of each activity can be reduced by incurring the cost shown in Table 2. Table 2 Activity Cost per Day of Reducing Duration of Maximum Allowable Reduction in Activity Duration of Activity (Days) A S500 2 S400 3 S300 5 D S350 E S150 2 F S100 G $250 8 4 8 9 B 2 4 4 a) Draw the project diagram. b) Determine the critical path and critical activities and estimated the shortest duration for the completion of this phase. c) Determine the slack time for each activity. d) If we want to reduce the total project duration by 2 days, what is the most economical way to do it? e) Assume that the project must be completed in 30 days, what is the most economical way to get the project done