20. Select the correct answer.
What kind of economy does the United States have?

A.
The United States has a single-resource economy because it is capable of producing most of the food and natural resources needed by its citizens.
B.
The United States has a diversified economy because certain of its exports, such as airplanes, are used by different nations all around the world.
C.
The United States has a diversified economy because it exports a wide range of goods, including soybeans, oil, and airplanes.
D.
The United States has a single-resource economy because its top exports are food products, such as soybeans, meat, and poultry.