Bobby Dole recently sold a 15-year $1,000 face value bond at a discount for $730 that net the firm $700 after flotation costs. The low coupon bond has a 6% coupon with interest paid annually. If Bobby Dole has a marginal tax rate of 40 percent, what is its after-tax cost of debt for these bonds?

A) 7.8%

B) 5.96%

C) 9.2%

D) 7.09%