What does it mean by the statement “Melodies are sung antiphonally"?

1. One choir singing in alternation with another.
2. Other are sung in response style - with one or more soloist answered the full choir.

A. Statement 1 alone could explain the statement
B. Statement 2 alone could explain the statement
C. Both statement 1 and 2 explain the statement
D. Neither statement 1 nor 2 could explain the statement​