The Price Index in the First Year Is 100, in the Second

Multiple Choice

The price index in the first year is 100, in the second year is 90, and in the third year is 80. What is the deflation rate between the first and second year, and between the second and third year?

A) 11 percent between the first and second year, 11 percent between the second and third year
B) 11 percent between the first and second year, 12 percent between the second and third year
C) 10 percent between the first and second year, 11 percent between the second and third year
D) 10 percent between the first and second year, 12 percent between the second and third year