activities and their optimistic completion time, the most likely completion time, and the pessimistic completion time $($all in days$)$ for a new contract are given in the following table:

$\backslash$table$[[,$Time $($days$),$Immediate,,Time $($days$),$Immediate$],[$Activity$,a,m,b,$Predecessor$($s$),$Activity,$a,m,b,$Predecessor$($s$)],[$A$,3,7,9,-,$G$,6,10,15,$A$,$ E$],[$B$,3,4,5,-,$H$,10,11,12,$F$],[$C$,2,3,4,-,$I,$5,7,9,$G$],[$D$,7,8,9,$C$,$J$,15,17,19,$C$],[$E$,2,4,6,$B$,$ D$,$K$,4,8,12,$H$,$ I$],[$F$,2,3,4,$A$,$ E$,,,,,]]$

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

b$)$ Activities on the critical path for the project are