Given a nominal interest rate of 6 percent, in which of the following cases would you earn the lowest after-tax real rate of interest?
选项：

A:Inflation is 4 percent; the tax rate is 5 percent;
B:Inflation is 3 percent; the tax rate is 20 percen;
C:Inflation is 2 percent; the tax rate is 30 percent.;
D:The after-tax real interest rate is the same for all of the above