You are given the following information about a project consisting of fifteen activities: Activity Predecessors Normal Time (days) 3 Crash Time (days) 3 Normal Cost Crash Cost A $ 1,500 $ 1,500 B A 14 10 $ 500 $ 800 A 1 1 $ 500 $ 500 D 3 2 $ 300 $ 350 E 1 1 $ 400 $ 400 F 2 2 $ 300 $ 300 G D, E, F 1 1 $ 300 $ 300 H G 1 1 $ 100 $ 100 I H 3 2 $ 300 $ 500 J H 2 1 $ 200 $ 300 K I, J 2 1 $ 100 $ 150 L K 2 1 $ 200 $ 300 M L 4 2 $ 100 $ 200 N L 1 1 $ 300 $ 300 O B, M, N 3 1 $ 2.000 $ 4,000 a) Construct the project network for this project (activity on node). b) Find the earliest start (ES), Latest Start (LS), Earliest Finish (EF), Latest Finish (LF) and Slack for each activity. c) Determine the Critical path & Project completion time. d) Crash the project to 20 days at least cost