If the Parity Ratio Goes from 0

If the parity ratio goes from 0.8 to 0.7, it means that the prices received by farmers had

A) fallen by 12.5 percent relative to the prices they paid.
B) fallen by 10 percent relative to the prices they paid.
C) risen by 12.5 percent relative to the prices they paid.
D) risen by 10 percent relative to the prices they paid.