The correct answer is (a)"A Crazy Blues."
"A Crazy Blues" is the first recording of blues music by an African American. Mamie Smith and Her Jazz Hounds recorded this song in 1920. It was composed by Perry Bradford. Bradford wanted to market Jazz and Blues music performed by African Americans, but he had a difficult time convincing the record companies in New York that the albums would sell despite his design of the songs being intended to appeal to white audiences. The record ended up being a smash hit and sold over a million copies.
Duke Ellington's "Cotton Tail" from 1940 had no lead in like traditional jazz songs, and it follows a different form, breaking from the usual thirty-two bar form. After a run-through of the main theme, Ellington introduced a new four-bar theme. This form changed the direction of jazz.