$18.$"Topstone Industries has an expected EBIT of $$1,000,000.$ Its unlevered cost of capital is $11\%$ and its cost is debt of $5\%.$ Topstone's debt$-$to$-$equity ratio is $1/3.$ The corporate tax rate is $25\%.$ What is the appropriate discount rate to be used under the FTE method to value Topstone?"

$12\mathrm{.}5\%$

$13\mathrm{.}6\%$

$10\mathrm{.}0\%$

$11\mathrm{.}0\%$

$16\mathrm{.}3\%$