PROBLEM FOUR: 20MARKS. A project has these activities, precedence relationships, and activity durations: Activity Immediate predecessor activities Activity duration (days) Activity Immediate predecessor activities Activity duration (days) A ---- 7 E B 19 B ----- 10 F A 21 C A 14 G C, D 14 D B 12 H F, G, E 8 a. Draw a CPM network for the project. 6marks b. Computing the duration for each path also tabulate the (EF, LF, ES, LS) times. 10marks c. What is the critical path? What is the project's estimated duration? 4marks