Unbelievable as it is, the film 2012 without doubt________ a warning that human beings are faced with potential dangers

A. belongs to         B. serves as               C. exists in                       D. accounts for

Unbelievable as it is, the film 2012 without doubt______ a warning that human beings are faced with potential dangers.

1. A.
   belongs to
2. B.
   serves as
3. C.
   exists in
4. D.
   accounts for