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
Anaesthetic circuit that prevents rebreathing of CO2 
Select and explain. 
A. Magil's circuit, B. Mapleson D circuit, C. Ayre's piece, D. Circle system
D: Circle system
Answer: D: Circle system 
Explanation: 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