This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
[{'content': 'Killed vaccine is \nSelect and explain. \nA. Hepatitis A, B. Measles, C. OPV, D. BCG', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hepatitis vaccine-2 types Formaldehyde inactivated vaccine Live attenuated vaccine -administered as a single subcutaneous dose (refer pgno:212 park 23 rd edition)', 'role': 'assistant'}]