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': "Anaesthetic circuit that prevents rebreathing of CO2 \nSelect and explain. \nA. Magil's circuit, B. Mapleson D circuit, C. Ayre's piece, D. Circle system", 'role': 'user'}, {'content': 'Answer: D \nExplanation: Different anaesthetic breathing circuits are Mapleson circuits and circle system. Circle system is a closed circuit, so called because it has inbuilt CO2 absorbers. It prevents rebreathing of exhaled air', 'role': 'assistant'}]