Rockingham Motors issued a 30-year, 8 percent semiannual bond 3 years ago. The bond currently sells for 103.1 percent of its face value. The company's tax rate is 21 percent. What is the after tax cost of debt?

2.72%

5.99%

5.10%

5.69%

6.10%

If you can, can you please apply steps, struggling with this one thanks!