13.5 Shanken Corp. issued a 30-year, 6.2 percent semiannual bond 7 years ago. The bond currently sells for 108 percent of its face value. The company's tax rate is 35 percent. a. What is the pre-tax cost of debt? b. What is the after-tax cost of debt? c Which is more relevant, the pre-tax or the after tax cost of debt? Why