A 5-year corporate bond yields 10.70%. A 5-year municipal bond of equal risk yields 6.50%. 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. 40.04% b. 39.25% c. 34.15% d. 47.50% e. 34.93%