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': 'Vaccines are sterilized by? \nSelect and explain. \nA. Seitz filtration, B. Hot air oven, C. Autoclaving, D. Heat inactivation', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Vaccines may be prepared by heat inactivation of bacteria. Thus heat can be employed to free the vaccine from other contaminants. REF:Textbook of microbiology Ananthanarayan, and Paniker.', 'role': 'assistant'}]