Which of the following was a major concern for the National Grange?

corporate income tax

manufacturing prices

railroad monopolies

urban poverty

The national grange was a bunch of farmers, so D is off the list, as is B.

A is about corporations; not a lot to do with farmers, again.

C, though - railroads totally revolutionized farming industry, because now farmers could sell to people far away. But if one railroad company dominated the industry, they could hike the prices ridiculously high, which irritated the National Grange.