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': 'Choana is: \nSelect and explain. \nA. anterior nares, B. Posterior nares, C. Tonsils, D. Larynx', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Posterior nares Nasal cavity: Nasal fossae are two irregular cavities extending from the mucocutaneous junction with the nasal vestibule in front(anterior nares) to the junction with the nasopharynx behind(posterior nares or choanae) Ref.Dhingra 5/e,p 150.6/e,p 135.', 'role': 'assistant'}]