PVE, Inc. has $$15$ million of debt outstanding with a coupon rate of $9\%.$ Currently, the yield to maturity on these bonds is $7\%.$ If the firm's tax rate is $35\%,$ what is the after $-$ tax cost of debt to PVE?

A$.10\mathrm{.}76\%$

B$.5\mathrm{.}85\%$

C$.4\mathrm{.}55\%$

D$.5\mathrm{.}4\%$