This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
Sphenoidal air sinus is supplied by which nerve: 
Select and explain. 
A. Posterior ethmoidal, B. Posterior superior, C. Sphenoidal, D. Infratemporal
A: Posterior ethmoidal
Answer: A: Posterior ethmoidal 
Explanation: Posterior ethmoidal nerve enters the posterior ethmoidal foramen and supplies the ethmoidal and sphenoidal air sinuses.