An 7.8% coupon bond issued by the state of Indiana sells for $1,000. What coupon rate on a corporate bond selling at its $1,000 par value would produce the same after-tax return to the investor as the municipal bond if the investor is in: a. the 15% marginal tax bracket? Do not round intermediate calculations. Round your answer to two decimal places. % b. the 25% marginal tax bracket? Do not round intermediate calculations. Round your answer to two decimal places. % c. the 35% marginal tax bracket? Do not round intermediate calculations. Round your answer to two decimal places. %