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
[{'content': 'Sphenoidal air sinus is supplied by ___________ nerve: \nSelect and explain. \nA. Posterior ethmoidal nerve, B. Posterior superior alveolar nerve, C. Sphenoidal nerve, D. Infratemporal nerve', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]