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: Unknown
[{'content': 'All are true about streptococcus except: \nSelect and explain. \nA. M-protein is responsible for production of mucoid colonies, B. M- protein is responsible for virulence, C. Mucoid colonies are virulent, D. No resistance to penicillin has been reported', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Mucoid colonies are due to production of capsule of hyaluronic acid not due to M-protein. Growth characteristic of strep. Pyogenes:\nOn blood agar virulent stains form matt or mucoid colones while avirulent from glossy colonies.\nM, T, R are proteins found on outer part of cell wall and forms the basis of Griffith classification.\nM protein – acts as virulence factor and antibody against it are protective.\nT and R protein – No relation to virulence', 'role': 'assistant'}]