Cookie Dough Manufacturing has a target debt$-$equity ratio of $\mathrm{.}6.$ Its cost of equity is $15$ percent, and its pretax cost of debt is $9$ percent. What is the WACC given a tax rate of $21$ percent?

$15\%$

$9\%$

$12\mathrm{.}04\%$

$11\mathrm{.}76\%$

$7\mathrm{.}11\%$

$12\mathrm{.}75\%$