Ju Hua Tai is a popular song among young people, ___were often heard singing it in Karaoke.

  A. which      B. who      C. that         D. what

Ju Hua Tai is a popular song among young people, ___were often heard singing it in Karaoke.

1. A.
   which
2. B.
   who
3. C.
   that
4. D.
   what