A 7-year municipal bond yields 5.50%. Your marginal tax rate (including state and federal taxes) is 32.00%. What interest rate on a 7-year corporate bond of equal risk would provide you with the same after-tax return? (Round your final answer to two decimal places.)

a. 17.19%

b. 7.26%

c. 8.09%

d. 3.74%

e. 4.17%