help please

Opelika Inc., a U.S. multinational corporation issued a 25 -year 8% semiannual bond 9 years ago in the global market. The bond currently sells for $1,020 per bond. If the company's marginal tax rate is 40%, what is the yield to maturity on the bond and the after-tax cost of debt to the company? (Rounded) 7.78%;4.67% 7.75%;3.10% 7.88%;4.67% 3.89%;2.33% 3.87%;1.55%