Sunland has determined that it could issue $1000 face value bonds with an 10 percent coupon paid semiannually and a 5-year maturity at $939.63 per bond. If Sunlands marginal tax rate is 40 percent, its after-tax cost of debt is closest to: A_6.6 percent.,B_7.0 percent., C_7.3 percent., D_6.7 percent.