This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
[{'content': 'Heart lung machine is sterilized by \nSelect and explain. \nA. Orthophthaldehyde, B. Cidex, C. Isopropyl alcohol, D. Ethylene oxide', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ethylene oxide is used for sterilization of many heat sensitive items such as heart - lung machine, sutures, catheters and dental equipment.', 'role': 'assistant'}]