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': 'Most common age group affected by streptococcus pyogenes \nSelect and explain. \nA. <5 years, B. 5-15 years, C. 20-25 years, D. 30-40 years', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Sore throat(tonsilitis) is the most common manifestation of streptococcal infection and affects 5-15 years age group.', 'role': 'assistant'}]