QUESTION $17$

A simple project listing of five activities, their predecessors, and their respective time estimates are presented here: Activity Immediate Predecessor Time in Days

$\backslash$table$[[$A$,$None,$2],[$B$,$A$,2],[$C$,$A$,1],[$D$,$B and C$,3],[$E$,$D$,1]]$

Using the CPM$,$ which activities have slack in this project?

C

D

C and $E$

A

B

QUESTION $18$