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: ENT
[{'content': 'The site of origin of angiofibroma - \nSelect and explain. \nA. Roof of nasopharynx, B. Anterior wall of sphenoid bone, C. Posterior part of nasal cavity close to the sphenopalatine ganglion, D. Lateral wall of nasal cavity', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The most common site is posterior part of nasal cavity close to the margin of sphenopalatine foramen.\nThe tumor starts adjacent to the sphenopalatine foramen. Large tumors are frequently bilobed or dumbbell-shaped, with one portion of tumor filling the nasopharynx and the other portion extending to the pterygopalatine fossa.', 'role': 'assistant'}]