This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anesthesia Machine, Subject name: Anaesthesia
[{'content': 'Color of oxygen cylinder is: \nSelect and explain. \nA. Black with white color, B. Blue with white color, C. Yellow with white color, D. White', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ANSWER: (A) Black with white colorREF: Fundamentals of Anesthesia, Tim Smith Colin Pinnock Ted Lin, 3rd Ed, p830SubstanceColour codingCylinderShoulderOxygenblackwhiteNitrous oxideblueblueEntonox gasblueWhite/blueAirblackWhite/blackCarbon dioxidegreygrey', 'role': 'assistant'}]