Activity name. Duration predecessors

A$-7-$none

B$-3-$a

C$-8-$a

D$-2-$b$,$c

E$-5-$d

A$.$activity C can be delayed by one day without delaying the overall project

b$.$ the latest activity D can start without delaying the project is on day $15$

C$.$ float for activity D is equal to $0$ therefore it is not an activity along the projects critical path

D$.$ activity a is on the critical path which means late finish equals early start