plz answer a,b,c part in clearly.

4. The chief engineer of firm XYZ is responsible for supervising the construction work of a road. He has identified the activities and their durations for each stage of operation. Preceding activities Activity A B D E F G H I J K L M Duration (days) 5 10 1 8 10 9 3 7 4 3 5 8 4 B B B A,D A.D F F C.J H,E,I,K CJ a. Draw a network diagram (AOA) for this road construction project. (3) b. Which are the critical activities? (1) How long the project will take? (1) c