In New England and elsewhere there are fine dairy, fruit, and vegetable farms, but the richest farmlands of the world lie in the American Middle West. Enormous crops of corn and wheat are grown there. Some of the corn and wheat is sold to feed people of the United States and other countries, but most of it is used to fatten pigs and cattle. Pork and beef, in turn, are sold as food. There are several reasons why the Middle West is so favorable for farming. The soils are rich and deep. There is usually just the right combination of sun and rain. There is a long enough period in late spring, summer, and early fall when no frost comes to kill the crops. The land is mostly level, so that modern farm machinery can be easily used. Perhaps most important, American farmers have learned from scientists in colleges and universities how to raise better crops and animals, and how to get the most out of the soil without destroying it.
The Midwestern and northeastern parts of the United States are the world's richest farming regions, but they are also the world's busiest factory regions. These two facts work together. The millions of city dwellers who work in the factories cannot live without the products of the farms, such as the wholesome milk that comes from the glistening Wisconsin dairy farm. Farmers, in turn, need the farm machinery, the automobiles and trucks, and many other products made by the city dwellers.
Most of corn and wheat is______________.

A. sold to feed people
B. exported to foreign countries
C. sold to fatten cattle and pigs
D. sold as food