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
Heart lung machine is sterilized by 
Select and explain. 
A. Orthophthaldehyde, B. Cidex, C. Isopropyl alcohol, D. Ethylene oxide
D: Ethylene oxide
Answer: D: Ethylene oxide 
Explanation: Ethylene oxide is used for sterilization of many heat sensitive items such as heart - lung machine, sutures, catheters and dental equipment.