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': 'Vaccine is NOT available against which serotype of Neisseria meningitidis? \nSelect and explain. \nA. A, B. B, C. C, D. Y', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Bivalent (groups A and C) or tetravalent (against groups A, C, Y and W-135) vaccines are available for protection against meningococcal meningitis. Ref: Park 21st edition, page 151.', 'role': 'assistant'}]