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: Social & Preventive Medicine
[{'content': '. True about polio is all except: \nSelect and explain. \nA. Sabin vaccine is attenuated, oral vaccine, B. Salk is a killed formalized vaccine used, C. Vaccine induced polio is usually due to Type 2 virus, D. Most common type of virus in epidemics is Type 1', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Vaccine induced polio" is usually due to Type 2 virus', 'role': 'assistant'}]