A firm can issue $$1,000$ par value bond that pays $$100$ per year in interest at a price of $$980.$ The bond will have a $5-$year life. The firm is in a $35\%$ tax bracket. What is the after tax cost of debt?

A$.10\mathrm{.}53\%$

B$.10\mathrm{.}20\%$

C$.6\mathrm{.}85\%$

D$.6\mathrm{.}50\%$