The art center is ______ used to be Factory 789 and _______ millions of tractors were made.

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

The art center is ______ used to be Factory 789 and _______ millions of tractors were made.

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

The art center is ______ used to be Factory 789 and _______ millions of tractors were made.

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