Which statement describes a cause of "black blizzards" [large, dark dust clouds] that occurred on the Great Plains during the Dust Bowl?

The misuse of the land and the severe drought combined to create the Dust Bowl - a vast, parched area in the Midwest. The Dust Bowl affected one hundred million acres of land. The resulting black blizzards happened when millions of tons of dirt were swept from the parched, barren fields and swirled up into the air.

Both the han and the roman empire decline as a result of social unrest during their collapse.

Idont know which one is right   but i know that c is wrong and a might be wrong