Assume that the activity time estimates $($in days$)$ for the swimming pool construction project in Problem $11$ are as follows:

$\backslash$table$[[$Activity$,$Optimistic,Most Probable,Pessimistic$],[$A$,3,5,6],[$B$,2,4,6],[$C$,5,6,7],[$D$,7,9,10],[$E$,2,4,6],[$F$,1,2,3],[$G$,5,8,10],[$H$,6,8,10],[$I$,3,4,5]]$

a$.$ What are the critical activities?

b$.$ What is the expected time to complete the project?

c$.$ Based only on the critical path, what is the estimated probability that the project can be completed in $25$ or fewer days?