Sarensen Systems Inc. is expected to pay a dividend of $$2\mathrm{.}50$ at year end $($D$),$ the dividend is expected to grow at a constant rate of $5\mathrm{.}50\%$ a year, and the common stock currently sells for $$37\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?