Given that its debt is $$600,000,$ its leverage value is $$679,800,$ a tax rate of $33\%,$ a cost of debt $($unleveraged$)$ of $17$ and a cost of debt of $13\%,$ what is this firm's cost of equity?

a$.35\mathrm{.}33\%$

b$.36\mathrm{.}49\%$

c$.37\mathrm{.}15\%$

d$.38\mathrm{.}20\%$