Which of the following explains why jazz music gained popularity in the United States in the 1920s? A
American soldiers who fought in France during World War I learned about jazz from European musicians.
B
African American musicians from the South migrated to northern cities where more people could hear their music.

C
New industrial techniques made possible the mass production of the special musical instruments needed to play jazz.

D
Mass immigration from southern and eastern Europe brought new cultural forms, including jazz music, to the United States.