This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
[{'content': 'Formaldehyde gas sterilization is employed for? \nSelect and explain. \nA. Sterilizing hea lung machines, B. Glass materials, C. Paper and cloth, D. Fumigation of operation theater', 'role': 'user'}, {'content': "Answer: D \nExplanation: Formaldehyde gas is used for sterilising instruments and heat sensitive catheters and for fumigating wards and sick rooms and laboratories REF:Ananthanarayan and Panicker's Textbook ofMicrobiology 8thEdition pg no:36", 'role': 'assistant'}]