The durations associated with each activity in a project are shown below, as well as the logical dependencies among the activities.

$\backslash$table$[[$Activity$,$Pred.,Duration,ES$,$EF$,$LS$,$LF$,$TF$],[$O$,--,0,,,,,],[$A$,$O$,3,,,,,],[$B$,$O$,5,,,,,],[$C$,$A$,6,,,,,],[$D$,$A$,2,,,,,],[$E$,$D$,3,,,,,],[$F$,$D$,3,,,,,],[$G$,$B$,4,,,,,],[$H$,$F$,$G$,5,,,,,],[$I$,$C$,4,,,,,],[$J$,$E$,$I,$2,,,,,],[$K$,$J$,3,,,,,],[$T$,$H$,$K$,0,,,,,]]$

a$.$ Neatly draw the CPM network diagram.

b$.$ Compute the early times, late times, and total floats for each activity, and identify the critical path.

c$.$ What could activity $O$ be in a typical construction project?

d$.$ What could activity $T$ be in a typical construction project?