Suppose that MNINK Industries$$ capital structure features $64$ percent equity, $8$ percent preferred stock, and $28$ percent debt. Assume the before$-$tax component costs of equity, preferred stock, and debt are $11\mathrm{.}80$ percent, $9\mathrm{.}70$ percent, and $9\mathrm{.}00$ percent, respectively.

What is MNINK$$s WACC if the firm faces an average tax rate of $21$ percent and can make full use of the interest tax shield?