This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nose and paranasal sinuses, Subject name: ENT
Onodi cells and Haller cells are seen in relation to 
Select and explain. 
A. optic nerve and floor of orbit, B. Optic nerve and frontal sinus, C. Optic nerve and ethmoidal air cells, D. Orbital chiasma and Nasolacrimal duct
A: optic nerve and floor of orbit
Answer: A: optic nerve and floor of orbit 
Explanation: The onodi cells and haller cells are posterior ethmoidal air cells. Onodi cell: Posterior ethmoidal cell which may grow posteriorly by the side of sphenoid sinus or superior to it for as much distance as 1.5 cm from the anterior surface of sphenoid. Hallercells: Air cells situated in the roof of maxillary sinus. Ref.Dhingra 5/e,p 153.