Sorensen Systems Inc. is expected to pay a $$2\mathrm{.}50$ dividend at year end $($D$1=$ $$2\mathrm{.}50,$ the dividend is expected to grow at a constant rate of $5\mathrm{.}50\%$ a year, and the common stock currently sells for $$67\mathrm{.}50$ a share. The before$-$tax cost of debt is $7\mathrm{.}50\%,$ and the tax rate is $40\%.$ The target capital structure consists of $45\%$ debt and $55\%$ common equity. What is the company's WACC if all the equity used is from retained earnings?

$6\mathrm{.}02\%$

$7\mathrm{.}09\%$

$5\mathrm{.}95\%$

$6\mathrm{.}24\%$

$5\mathrm{.}88\%$