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': 'Congenital passive immunity is NOT found in - \nSelect and explain. \nA. Polio, B. Mumps, C. Rubella, D. Measles', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The maternal antibodies gradually disappear during the first 6 months of life. Immunity following injection is fairly solid although reinfection can occur since infection with one type does not protect completely against the other 2 types of viruses (refer pgno:205 park 23rd edition)', 'role': 'assistant'}]