Given the project within the table below, calculate the following:

$\backslash$table$[[$Activity$,\backslash$table$[[$Duration$],[($hours$)]],\backslash$table$[[$Immediate$],[$Predecessors$]]],[$A$,4,$None$],[$B$,8,$None$],[$C$,6,$A$],[$D$,7,$B$,$ C$],[$E$,3,$D$],[$F$,1,$E$],[$G$,5,$E$,$ F$],[$H$,4,$G$]]$

a$.$ What is the project's minimum completion time?