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': 'Chemoprophylaxis is indicated for all of the following except: \nSelect and explain. \nA. Cholera, B. Measles, C. Meningococcal meningitis, D. Conjunctivitis87. Under the school vision screening', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. b. Measles', 'role': 'assistant'}]