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 gonococci Includes all except \nSelect and explain. \nA. Outer membrane protein, B. IgA1 Protease, C. M Protein, D. Transferrin', 'role': 'user'}, {'content': 'Answer: C \nExplanation: M Protein is a virulence factor produced by Streptococcus.', 'role': 'assistant'}]