A project to organize a grocery store in anticipation of its grand re-opening has the following activities. Activity Duration Predecessors A 2 0 B 15 0 C 8 0 D 4 A,B E 7 B,C F 3 D,E G 5 E,F H 10 G I 4 G a) what are the critical path activities b) What is the project completion time? c) What is the lastest finish time (LF) for Activity D? D) What is the slack or float for activity H? E) What is the slack or float for Activity B?