Sport Fishing Expeditions has a debt$-$equity ratio of $0\mathrm{.}80.$ The pre$-$tax cost of debt is $7\%$ and the required return on assets is $15\%.$ What is the cost of equity if we factor in the firm's tax rate of $23\%?$

$20\mathrm{.}53\%$

$19\mathrm{.}93\%$

$18\mathrm{.}91\%$

$21\mathrm{.}12\%$

$21\mathrm{.}72\%$