Here is a network with the activity times shown in days:

a$.$ Find the critical path.

$A-C-D-F-G$

$A-C-D-E-G$

$A-B-D-E-G$

$A-B-D-F-G$

The following table shows the normal times and the crash times, along with the associated costs for each activity.

b$-1.$ If the project is to be shortened by four days, which activities, in order of reduction, would be shortened?

$A,C,D(orF),F(orD)$

$C.F(orE),D(orE)$

$E.A$

$A.F.D(orE)$

$b-2.$ Find the resulting cost to crash.