Question

Yao Juan is the only one of the students who_________to be praised

1. A.
   are
2. B.
   have been
3. C.
   is
4. D.
   has been

Answer 1

C
one of the students +定语从句，（从句谓语用复数）
the only one of the students +定语从句，（从句谓语用单数）
前后时态一致。