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': 'Which is not a part of hypopharynx - \nSelect and explain. \nA. Posterior cricoid region, B. Ary epiglottic folds, C. Posterior pharyngeal wall, D. Pyriform fossa', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]