If a $20,000$ SF office building has a full service gross lease at $$3\mathrm{.}25$ per month rent$/$SF$,$ vacancy$/$collection loss is $5\%,$ expenses are $$1\mathrm{.}25$ per month$/$SF what are the following:

$4$a $$ What is the annual PGI $4$b $$ What is the annual EGI $4$c $$ What is the annual NOI