It is reported that no problems have been discovered in milk products such as Yili, Sanlu and Mengniu, ________ proves newly-produced liquid milk safe.

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

It is reported that no problems have been discovered in milk products such as Yili, Sanlu and Mengniu, ________ proves newly-produced liquid milk safe.

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

It is reported that no problems have been discovered in milk products such as Yili, Sanlu and Mengniu, ________ proves newly-produced liquid milk safe.

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