The great plains are also referred to

a. marshes c. interior plains b. lowlands d. plateaus

[b is incorrect]

The Great Plains are also referred to as interior plains.

Explanation:

The Great Plains form a huge part of the "interior plains" that stretch from Canada to the central United States. These plains are home to bunchgrass steppes, shortgrass and tallgrass prairies, and a few other less-known species of stunted shrubs. The black and brown fertile soils favor the cultivation of grain plants. These plains are thus known for their production of wheat and other grains.