In the Late-19^th Century, Farmers Blamed Their Problems on a Number

In the late-19^th century, farmers blamed their problems on a number of factors. Which of these complaints is supported (somewhat) by quantitative evidence gathered by economic historians?

A) Eastern bankers conspired to inflate interest rates on western farm mortgages.
B) Manufacturers charged unreasonably high prices for farm equipment.
C) Consumer goods prices were rising too rapidly.
D) Certain sections of railroad were monopolized, resulting in unreasonably high freight rates.