Suppose the Tax Rate on Interest Income Is 25 Percent

Suppose the tax rate on interest income is 25 percent, the real interest rate is 4 percent, and the inflation rate is 4 percent.In this case, the real after-tax interest rate is

A) .5 percent.
B) 3.5 percent.
C) 1.0 percent.
D) 4.0 percent.
E) 2.0 percent.