Suppose you bought a one-year Treasury bill with a nominal interest rate of 1%. The expected inflation rate at that time was 1%. One year later, you find out that the aggregate price level actually decreased at an annual rate of 1%. Your actual real rate of return on the T- bill is estimated to be

a) 1%

b) 2%

c) -1%

d) -2%

I know the answer is b), but I don't get how to get there