Flagstar is an all equity firm and has a cost of capital of $8\mathrm{.}5$ percent. The firm is considering switching to a debt$-$equity ratio $($D$/$E$)$ of $0\mathrm{.}70$ with a pretax cost of debt of $6$ percent. What will the firm's cost of equity be if the firm makes the switch? The tax rate is $25\%.$

$9\mathrm{.}81\%$

$10\mathrm{.}32\%$

$10\mathrm{.}60\%$

$10\mathrm{.}94\%$

$11\mathrm{.}43\%$