The required return on equity for an all$-$equity firm is $12\mathrm{.}0$ percent. They are considering a change in capital structure to a debt$-$to$-$equity ratio of $\frac{1}{2},$ the tax rate is $34$ percent, the pre$-$tax cost of debt is $8$ percent. Find the nell cost of capital if this firm changes capital structure.

$10\%$

$8\mathrm{.}43\%$

$10\mathrm{.}64\%$

$8\mathrm{.}67\%$