Donald Investments has a target debt$-$to$-$equity ratio of $0\mathrm{.}8.$ Given that the after$-$tax cost of debt is $5\mathrm{.}6\%$ and that the company$$s weighted average cost of capital is $10\mathrm{.}8\%,$ its cost of equity is closest to:

Group of answer choices

$4\mathrm{.}62\%$

$14\mathrm{.}96\%$

$31\mathrm{.}60\%$