I need complete answer for question C

Construction of a building is based on the following CPM network: Predecessor Activity B Successor B, C, D E mU AU A B, A A B C, D E, F, D Normal Time 6 8 2 3 5 5 6 Normal Cost $ 100 80 40 80 80 60 Crash Time 2 2 1 2 3 1 2 Crash Cost $ 150 140 60 120 140 100 160 F G G G 120 Draw the network and answer the following questions. a. What are the normal project completion time and normal cost? Normal completion time 27 days Normal cost $ 560 b. Identify the critical path. (You may select more than one answer. Single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer.) A-D-G A-B-C-F-G A-C-F.G A-B-E-G A-D-F-G c. How much additional cost is needed to crash the project by one day? Additional cost $ 40 to crash one day off the project This can be accomplished most effectively by crashing any one of which three activities below? (You may select more than one answer. Single click the box with the question mark to produce a check mark for a correct answer and double click the box with the question mark to empty the box for a wrong answer.) 2A B ?C 7 D E