Lannister Manufacturing has a target debt$-$equity ratio of $0\mathrm{.}68.$ Its cost of equity is $21$ percent, and its cost of debt is $12$ percent. If the tax rate is $32$ percent, what is the company's WACC?

Multiple Choice

$13\mathrm{.}36\%$

$15\mathrm{.}8\%$

$16\mathrm{.}59\%$

$12\mathrm{.}27\%$