A Company Must Perform a Maintenance Project Consisting of Seven

A company must perform a maintenance project consisting of seven activities.The activities,their predecessors,and their respective time estimates are presented below: $$\begin{array} { | l | l | l | l | } \hline & & \text { Immediate } & \\\hline \text { Activity } & \text { Designation } & \text { Predecessor } & \text { Time in Days } \\\hline \text { Break down both machines } & \text { A } & \text { None } & 3 \\\hline \text { Clean machine 1 } & \text { B } & \text { A } & 3 \\\hline \text { Clean machine 2 } & \text { C } & \text { A } & 3 \\\hline \text { Re-set machine 1 } & \text { D } & \text { B } & 4 \\\hline \text { Re-set machine 2 } & \text { E } & \text { C } & 2 \\\hline \text { Re-calibrate both machines } & \text { F } & \text { D and E } & 1 \\\hline \text { Final test } & \text { G } & \text { F } & 2 \\\hline\end{array}$$
Using CPM,which activities make up the critical path?

A) A,B,D,F,G
B) A,C,E,F,G
C) A,C,B,F,E
D) A,D,E
E) None of the above