15. Read the passage.
The Dust Bowl
During the 1930s, extreme drought and high winds made life incredibly difficult in the Great Plains region of the United States. In many areas, rainfall was forty percent less than normal. The soil became extremely
dry, and when strong winds blew, they created tremendous dust storms. These so-called "black blizzards" were so thick that they made daylight seem like dusk. During this terrible period, the Great Plains region of the
United States was named the "Dust Bowl." Over the next few years, the drought continued, and the winds created more dust storms. In some places, the drought and high winds lasted for eight years. Many people
wondered if the black blizzards would ever end.
What role does the underlined sentence serve in this paragraph?
A. It is a fact that serves as a supporting detail.
B. It is an example that serves as a supporting detail.
C. It is the topic sentence.
D. It is a statistic that serves as a supporting detail.