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: Microbiology
[{'content': "The major antigenic determinant of H. influenzae is- \nSelect and explain. \nA. 'M' protein, B. Capsular polysaccharide, C. Catalase, D. Coagulase", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]