Plane will be very large _______ flying will be very cheap

1. A.
   and
2. B.
   so
3. C.
   but
4. D.
   or

Plane will be very large _______ flying will be very cheap.

The plane ______ when we got to the airport.

A. had taken off      B. was taken off     C. will take off     D. is taking off