The Blues
by S. G. Rolph
1 The genre of music known as the blues originated in the American South at the beginning of the twentieth century. The name comes from "blue notes," which are sung or played at a much lower pitch than the rest of the song. Blue notes create a distinctive, often melancholy sound. Slaves often sang songs and spirituals while working, and this music formed the foundation of blues music. After the Civil War, many African Americans migrated north in search of jobs, and they took the blues with them.
2 Blues music changed in response to the urban environments of the North, with many musicians including more instruments in their songs. In the South, blues music usually consisted of a harmonica and a guitar. In cities like Chicago, musicians began to use electric guitars, drums, pianos, or saxophones. This broader range of instruments gave new blues its distinctive sound. In 1933, the Library of Congress sent John A. Lomax and his son Alan across the country to record folk songs, including blues. Over the next several decades, they gathered over 10,000 song recordings and 6,000 images. Thanks to the Lomax family, people across America could now hear the blues music of luminaries like Muddy Waters and Huddie "Lead Belly" Ledbetter. The Lomax collection at the American Folklife Center is an invaluable historical record of music from many cultural groups.
3 Blues music serves as a powerful influence in many modern genres of music, including rap, country, and rock — all of which feature prominent blue notes. Over the past century, the blues have become an integral part of American music. The history of the blues is bound up in the discrimination and suffering African Americans have faced for centuries. Blues music is an enduring tribute to the collective strength of spirit required to turn such suffering into art.
Question: Which of the following quotes from the passage is evidence of the central idea?