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': 'The WHO announced, immunisation is a primary responsibility of - \nSelect and explain. \nA. States, B. International community, C. Voluntary agencies, D. An individual', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., States", 'role': 'assistant'}]