Consider the following table of activities and resources.

Activity Predecessors Duration Resources

A $31$

B A $52$

C A $41$

D B $51$

E C $52$

F D$,$E $21$

Which activity $($activities$)$ should be delayed to smooth the project? $($enter letters only $-$ no spaces or punctuation$)$

By how many time periods does the $($first$)$ activity in the answer above need to be delayed? $($enter number only$)$