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': 'Not true about pyriform fossa \nSelect and explain. \nA. Most common site for cancer, B. Rich nerve supply, C. Aryepiglottic fold forms its medial border, D. Present on either sides of laryngeal opening', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]