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
[{'content': 'All are pneumatization patterns ot sphenoid sinus except: \nSelect and explain. \nA. Pre sellar, B. Post sellar, C. Concha bullosa, D. Conchal', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Three types of sphenoid sinus pneumatization patterns have been found.Pneumatisation patterns depend on the position of thr sinus in relation to the sella turcica. Ref Dhingra 6/e,p 188.', 'role': 'assistant'}]