Overlapping contacts on a bitewing radiograph result from the
1. malalignment of teeth.
2. increased vertical angulation of the x-ray beam.
3. incorrect horizontal angulation of the x-ray beam.
4. decreased vertical angulation of the x-ray beam.

(1) and (3)

(1) (2) (3)

(2) and (4)

(4) only

All of the above.