We are sure everything here____ by the time you come back from abroad in a few years.

1. A.
   had changed
2. B.
   will have changed
3. C.
   had been changed
4. D.
   will have been changed

We are sure everything here____ by the time you come back from abroad in a few years.

A. had changed                    B. will have changed    

C. had been changed             D. will have been changed