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': 'Most common sire for osteoma is: \nSelect and explain. \nA. Maxillary sinus, B. Ethmoid sinus, C. Frontal sinus, D. Sphenoid sinus', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Craniofacial osteomas are begin tumors often originating in the paranasal sinuses. The frontal sinus is the most frequent location followed by the ethmoid,Maxillary and sphenoid sinus,respectively Age of presentation=second to fifth decade with a male-female ratio-3:1. Ref .Scott Brown 7/e,Vol 2,p 1521.', 'role': 'assistant'}]