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': 'Streptococcus pyogenes shows pathogenicity by all except? \nSelect and explain. \nA. M protein, B. Pyrotoxin, C. Pili, D. Streptolysin O', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Pili Virulence factors of str. pyogenes Str. pyogenes forms several exotoxins and enzymes which contribute to its virulence, but M protein is the most impoant of these.", 'role': 'assistant'}]