High Road Tours has an after-tax cost of debt of 5.1 percent at its current tax rate of 34 percent. What will its after-tax cost of debt be if the tax rate drops to 21 percent? Assume all interest is tax deductible.

A) 6.10 percent

B) 5.92 percent

C) 6.17 percent

D) 4.03 percent

E) 4.47 percent