The soils common to the south eastern USA are called

The correct answer is D. mollisols.

Mollisols are a soil order that is characterized by dark, rich, and fertile soils. They are the most extensive soil order in the United States, covering about 20% of the country. Mollisols are found in the central and eastern United States, as well as in parts of Canada and Mexico.

Mollisols are formed in grassland and prairie ecosystems. They are typically well-drained and have a high organic matter content. This makes them ideal for agriculture, and many of the world’s major grain crops are grown in mollisol soils.

The other options are incorrect for the following reasons:

• Ultisols are a soil order that is characterized by their low fertility and high acidity. They are found in tropical and subtropical regions around the world.
• Alfisols are a soil order that is characterized by their moderate fertility and high base saturation. They are found in temperate and subtropical regions around the world.
• Aridisols are a soil order that is characterized by their low moisture content and high salinity. They are found in arid and semi-arid regions around the world.