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: Medicine
[{'content': "Streptolysin 'O' acts through- \nSelect and explain. \nA. N- muraminidase, B. Teichoic acid, C. Muramic acid, D. Cytochrome oxidase", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]