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': 'HAV is not destroyed by: \nSelect and explain. \nA. 0.5 ppm chlorine, B. 1:4000 formalin, C. UV radiation, D. Boiling at 100degC for 5 minutes', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a. 0.5 ppm chlorine', 'role': 'assistant'}]