You are tasked with selecting among several profitable projects. Your team has a limited budget of $$10,000.$ Project A requires an investment of $$4000$ and has a PI of $1\mathrm{.}3.$ Project B requires an investment of $$4000$ and has a PI of $1\mathrm{.}6.$ If you do both projects, what is the WAPI of your investment?

$($a$)\mathrm{.}75$

$($b$)1\mathrm{.}16$

$($c$)1\mathrm{.}30$

$($d$)1\mathrm{.}45$