Roger Ginde is developing a program in supply chain management certification for managers. Ginde has listed a number of activities that must be completed before a training program of this nature could be conducted. The activities, immediate predecessors, and times appear in the accompanying table:

$\backslash$table$[[$Activity$,$Immediate Predecessor$($s$),$Time $($days$)],[$A$,-,4],[$B$,-,7],[$C$,-,2],[$D$,$B$,10],[$E$,$A$,$ D$,4],[$F$,$C$,5],[$G$,$E$,$ F$,10]]$

This exercise contains only parts $b,c,$ and $d.$

b$)$ The critical activities for the leadership training program development project are