A 5-year corporate bond yields 9.50%. A 5-year municipal bond of equal risk yields 6.5%. Assume that the state tax rate is zero. At what federal tax rate are you indifferent between the two bonds? (Round your final answer to two decimal places.) a. 33.98% b. 25.40% c. 31.58% d. 32.99% e. 27.38%