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': 'Virulence factor of group. A beta hemolytic streptococci - \nSelect and explain. \nA. P. M, B. P. T, C. P. R, D. Lipotechoic acid', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., P. M M protein is the most impoant virulent factor for str. pyogenes.", 'role': 'assistant'}]