______ tourism developing, more and more people prefer to go travelling for a holiday.

A. As.      B. With    C. Upon     D. For

______ tourism developing, more and more people prefer to go travelling for a holiday.

1. A.
   As.
2. B.
   With
3. C.
   Upon
4. D.
   For

______ tourism developing, more and more people prefer to go travelling for a holiday.