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': 'Color of N2O cylinder is – \nSelect and explain. \nA. Black with white shoulders, B. White with black shoulders, C. Grey, D. Blue', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]