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': 'The commonest organism causing cellulitis is ? \nSelect and explain. \nA. Streptococcus pyogenes, B. Streptococcus faecalis, C. Streptococcus viridans., D. Microaerophilic streptococci', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Streptococcus pyogenes", 'role': 'assistant'}]