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': 'In anesthesia, fitting of wrong gas cylinder to the anesthesia machine can he prevented by: \nSelect and explain. \nA. Pin index system, B. Yolk assembly, C. Bodock seal, D. Gas analyser', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ref: Miller Textbook of Anaesthesia. 7th ed.Explanation:The Pin Index Safety System, or PISSIt is a safety system that uses geometric features on the yoke to ensure that pneumatic connections between a gas cylinder and a machine that uses pressurized gases are not connected to the wrong gas yoke.This system can be seen on an anesthesia machine.Each gas cylinder has a pin configuration to fit its respective gas yoke.O2: 2-5N2O: 3-5Air: 1-5CO2: 1-6Heliox: 2-4Entonox= 7', 'role': 'assistant'}]