Which Two Must Occur to Successfully Demonstrate the Ethmoidal and Sphenoidal

Multiple Choice

Which two must occur to successfully demonstrate the ethmoidal and sphenoidal sinuses on the SMV projection? (Select all that apply.)

A) Central ray aligned horizontal and enters perpendicular to IOML.
B) Patient must be recumbent.
C) IOML aligned parallel with the image receptor.
D) OML aligned parallel with the image receptor.