Given the picture below that shows a CPM$/$PERT network LP formulation in Excel, what can you say $($time is measured in weeks$)?$

a$.$ The project will last for $140$ weeks

b$.$ The project will last for $108$ weeks

c$.$ The critical path is $108$ weeks long

d$.$ The critical path is $32$ weeks long

e$.$ Activity $F$ is the most critical activity

f$.$ b and c