Painfree Inc. just issued a semiannual coupon bond, which has a coupon rate of 6.8% and matures in 20 years. The bond's price is $1,870 and the par value is $2,000. Assume a tax rate of 35%. The company's after-tax cost of debt is 3.47% 4.46% 5.11% 3.71% 4.83%