Which of the following quotes from the passage is evidence of the central idea?

A. The genre of music known as the blues originated in the American South at the beginning of the twentieth century.

B. In 1933, the Library of Congress sent John A. Lomax and his son Alan across the country to record folk songs, including blues.

C. The Lomax collection at the American Folklife Center is an invaluable historical record of music from many cultural groups.

D. Blues music is an enduring tribute to the collective strength of spirit required to turn such suffering into art.