Which of the following statements is correct?
A. Movie studios in the 1930s were very similar to the ones of the 1920s.
B. The radio was a source of information in both the 1920s and the 1930s.
C. Country and western music was popular during both the 1920s and the 1930s.
D. Fitzgerald wrote about the American dream in The Grapes of Wrath.