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': 'Measles vaccination is given at - \nSelect and explain. \nA. 9 months, B. At birth, C. 4 weeks, D. 8 weeks', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The WHO expanded programme on immunization recommends immunization at 9 months of age.\nNow, second dose of measles is also given at 16-24 months in National Immunization Schedule.', 'role': 'assistant'}]