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': 'Diffusion hypoxia is seen during – \nSelect and explain. \nA. Induction of anaesthesia, B. Recovering anaesthesia, C. Preoperatively, D. Postoperatively', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Concentration effect and secondary gas effect → During induction.\nDiffusion hypoxia → during recovery.\nAll these occurs with N2O only. (Now anaesthetic gas xenon also produces all these effects).', 'role': 'assistant'}]