The Invention of Parity Price Ratios Was Designed to Protect

The invention of parity price ratios was designed to protect farmers' purchasing power.Over the years, these parity price ratios have

A) been fixed at 100 percent
B) increased to approximately 125 percent of their initial value set in 1910-1914
C) been increasing at approximately 25 percent per year
D) been falling and are less than 50 percent of the 1910-1914 ratio
E) been volatile, increasing and decreasing sometimes dramatically, but still averaging approximately 100 percent of 1910-1914 levels, which was the long-run target