An investor purchases one municipal bond and one corporate bond that pay rates of return of 6% and 7.5%, respectively. If the investor is in the 20% tax bracket, his after-tax rates of return on the municipal and corporate bonds would be, respectively, _____.

4.80% and 7.5%

6% and 6.00%

7.20% and 6.00%

6% and 7.5%