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: Surgery
[{'content': 'Which of these is a definitive airway: \nSelect and explain. \nA. Orotracheal airway., B. Nasopharyngeal airway., C. Nasotracheal airway., D. LMA.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]