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: Unknown
[{'content': 'A double lumen tracheostomy tube all are true EXCEPT: \nSelect and explain. \nA. Easy to remove inner cannula, B. Easy to clean inner cannula, C. Easy to replace inner cannula, D. No inner cannula', 'role': 'user'}, {'content': 'Answer: D \nExplanation: ANSWER: (D) No inner cannulaREF: Dhingra 4th ed p. 414Double lumen tracheostomy tubes have an inner cannula inside an outer cannula. It is easier to remove, clean and replace the inner cannula.', 'role': 'assistant'}]