The AP axial Townes method will need which tube angle if IOML is perpendicular to the image receptor?

30 degrees caudal
25 degrees cephalic
30 degrees cephalic
37 degrees caudal

37 degrees caudal

Rationale: If IOML is aligned perpendicular to the IR, a 37 degree caudal tube angle is needed to accurately project the dorsum sellae within the foramen magnum. There is a seven degree difference between the OML and IOML.