$3\mathrm{.}7$ Task time estimates for a production line setup project at Robert Klassen's Ontario factory are as follows:

$\backslash$table$[[$Activity$,$Time $($in hours$),\backslash$table$[[$Immediate$],[$Predecessors$]]],[$A$,6\mathrm{.}0,-],[$B$,7\mathrm{.}2,-],[$C$,5\mathrm{.}0,$A$],[$D$,6\mathrm{.}0,$B$,$ C$],[$E$,4\mathrm{.}5,$B$,$ C$],[$F$,7\mathrm{.}7,$D$],[$G$,4\mathrm{.}0,$E$,$ F$]]$

a$)$ Draw the project network using AON.

b$)$ Identify the critical path.

c$)$ What is the expected project length?

d$)$ Draw a Gantt chart for the project.