Will Invests $20,000 of After-Tax Dollars (AT$)in Tax-Exempt Municipal Bonds

Will invests $20,000 of after-tax dollars (AT$) in tax-exempt municipal bonds which yield 5% per year.He reinvests the interest in the same bonds and holds the bonds for two years.Will's marginal tax rate is 25%.What is his after-tax accumulation at the end of two years?

A) $21,000
B) $21,528
C) $22,000
D) $22,050