This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anaesthetic equipments, Subject name: Anaesthesia
[{'content': 'As per ISO, color of N20 cylinder is \nSelect and explain. \nA. Blue, B. Black, C. White, D. Red', 'role': 'user'}, {'content': 'Answer: A \nExplanation: To differentiate color coding is given to the cylinders . Blue - N20 Black - N2 Orange - Cyclopropane Grey - Co2 Black body with white shoulder - O2 Black body with brown shoulder - Heliox ( Helium + 02 )', 'role': 'assistant'}]