How Can the Rate of Inflation Be Calculated

How can the rate of inflation be calculated?

A) By subtracting the real income from the nominal income.
B) By subtracting last year's price index from this year's price index.
C) By subtracting this year's price index from last year's price index,dividing the difference by this year's price index,and multiplying by 100.
D) By subtracting last year's price index from this year's price index and dividing the difference by last year's price index and multiplying by 100.
E) By dividing the real income by the nominal income and multiplying by 100.