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: Pharmacology
[{'content': 'Which of the following drug is used for mass prophylaxis for prevention of meningococcal meningitis \nSelect and explain. \nA. Ciprofloxacin, B. Rifampicin, C. Ceftriaxone, D. Minocycline', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Rifampicin was used formerly but now Ciprofloxacin is the preferred drug for mass prophylaxis for prevention of meningococcal meningitis.', 'role': 'assistant'}]