This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: FMGE 2019, Subject name: Pharmacology
[{'content': 'Colour of nitrous oxide cylinder is? \nSelect and explain. \nA. Blue, B. Blue body with white shoulder, C. White, D. Black', 'role': 'user'}, {'content': 'Answer: A \nExplanation: N2O (blue) Cyclopropane (orange) Oxygen (black & white) Entonox (blue & white)', 'role': 'assistant'}]