The Lincoln Company sold a $1,000 par value, noncallable bond several years ago that now has 25 years to maturity and a 6.00% annual coupon that is paid semiannually. The bond currently sells for $950 and the company's tax rate is 35%. What is the after-tax cost of debt for use in the WACC calculation?

a. 4.16%

b. 4.46%

c. 4.79%

d. 5.39%

e. 5.83%