Which does not explain why a large part of the Great Plains became known as the "Dust Bowl"?

AThe soil of the Great Plains was too rocky to support farming.
BFarmers did not practice crop rotation.
CLittle rain fell for several years.
DHigh winds blew away the topsoil on plowed land.

Verified Answer :

The option that does not explain why a large part of the Great Plains became known as the "Dust Bowl" would be that "The soil of the Great Plains was too rocky to support farming," since the soil was (usually) relatively fertile. 

The correct answer is A, as the option that doesn't explain why a large part of the Great Plains became known as the Dust Bowl is that the soil of the Great Plains was too rocky to support farming, as that statement is not true. The Great Plains are a very fertile area, with land suitable for agriculture and cattle raising.