An SMV cranial projection (Schueller method) with accurate positioning demonstrates

1. the nasal fossae just anterior to the ethmoid sinuses.
2. the mandibular mentum slightly posterior to the ethmoid sinuses.
3. an equal distance from the mandibular ramus to lateral cranial cortex on both sides.
4. the bony nasal septum aligned with the long axis of the exposure field.
a. 2 and 3 only
b. 1 and 3 only
c. 1, 3 and 4 only
d. 1, 2, 3, and 4

C