$10.$ Ace Electronics Shipping $($NYSE: AES$)$ has an optimal capital structure of $40\%$ debt, $10\%$ preferred stock, and $50\%$ common equity. The before$-$tax cost of debt, the cost of preferred stock, and the cost of common equity are $7\mathrm{.}5\%,10\%,$ and $14\%,$ respectively. AES is in the $28$ percent tax bracket. What is the WACC of AES?