This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Streptococci, 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: Ans. is 'b' i.e., 5 - 15 years o Sore throat (tonsillitis) is the most common manifestation of streptococcal infection and affects 5-15 years age group.", 'role': 'assistant'}]