If the Price Index in the First Year Was 80

If the price index in the first year was 80, in the second year was 100, and in the third year was 90, what did the economy experience?

A) 20 percent inflation between the first and second years and 10 percent inflation between the second and third years
B) 20 percent inflation between the first and second years and 10 percent deflation between the second and third years
C) 25 percent inflation between the first and second years and 10 percent inflation between the second and third years
D) 25 percent inflation between the first and second years and 10 percent deflation between the second and third years