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': 'Which of the following factor is mainly respon-sible for virulence in Streptococcus : \nSelect and explain. \nA. Carbohydrate, B. Streptokinase, C. Streptodornase, D. M protein', 'role': 'user'}, {'content': 'Answer: D \nExplanation: M Protein\n\nIt is major virulence factor of group A Strep. pyogenes.\nIt is hair like projection of cell wall.\nIt is of 80 types (basis of Griffith classification) so immunity is type specific.\nM protein is also found in Group G streptococci.\n\nRemember :\n\nCarbohydrate is used as the basis of Lancefields classification.\nStreptokinase or fibrolysin and streptodornase or DNAse liquefy pus so used in enzymatic debridement', 'role': 'assistant'}]