Final answer:
Folk-blues and rock and roll artists from the South gained attention through B)record labels and A)radio broadcasts, with radio being critical in popularizing the music and contributing to cultural integration.
Step-by-step explanation:
Folk-blues singers from the South were brought into the limelight primarily through record labels and radio broadcasts. The reach of radio as a live broadcast medium was instrumental in the dissemination of various musical genres, including blues and later rock and roll, which was initially popularized by Alan Freed. Furthermore, radio played a significant role in shaping American national identity and cultural perceptions.
The advent of rock and roll, with artists like Little Richard, Bill Haley, Chuck Berry, Fats Domino, and Buddy Holly, saw a massive rise in popularity due in large part to the medium of radio. Record labels, recognizing the economic demand, eventually began signing black musicians, leading to the commercial integration of music. This phenomenon, paired with the landmark Brown v. Bd. of Education decision, helped to break down racial barriers in the entertainment industry.
Moreover, the genre of rock and roll, often considered a fusion of uptempo blues, jazz, and country music, was a driving force in blurring social and racial lines during the 1950s. Rock and roll celebrated themes of freedom and youth, resonating with teenagers across the nation and leading to social changes that would challenge segregation norms of the era.