challenge: Who recorded Os Afro-sambas in 1966, a work considered a watershed in MPB for fusing African sound with samba?
  
  A. Caetano Veloso and Maria Bethânia
  B. Jorge Ben Jor and Gilberto Gil
  C. Antônio Carlos Jobim and Elis Regina
  D. Baden Powell, Vinícius de Moraes, and Quarteto em Cy
  Answer: 