Answer:
The correct answer is B. From the mid-1930s to 1940 over 2.5 million people had moved out of the Great Plains states in the center of the United States as a consequence of the Dust Bowl.
Explanation:
The Dust Bowl phenomenon of the 1930s was one of the worst ecological disasters of the 20th century. It was a drought that affected the plains and prairies that extend from the Gulf of Mexico to Canada. The drought lasted at least between 1932 and 1939, and was preceded by a long period of above average rainfall. The Dust Bowl effect was caused by persistent drought conditions, favored by years of soil management practices that left it susceptible to the action of wind forces. The soil, stripped of moisture, was lifted by the wind in great clouds of dust and sand so thick they hid the sun. The Dust Bowl multiplied the effects of the Great Depression in the region and caused the largest population displacement in a short space of time in the history of the United States. Three million people left their farms during the 1930s, and more than half a million emigrated to other states, especially to the west.
