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: Anaesthesia
[{'content': 'Least diffusion coefficient is for : \nSelect and explain. \nA. Isoflurane, B. Enflurane, C. Halothane, D. N20', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e N20', 'role': 'assistant'}]