Suppose a foreign investor who holds tax-exempt Eurobonds paying 10.50% is considering investing in an equivalent-risk domestic bond in a country with a 28% withholding tax on interest paid to foreigners. If 10.50% after-tax is the investor's required return, what before-tax rate would the domestic bond need to pay to provide the required after-tax return?

a. 14.58%

b. 12.83%

c. 15.46%

d. 16.33%

e. 16.92%