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': 'Streptococcal pneumoniae presents at \nSelect and explain. \nA. <5 years, B. 5-15 years, C. 20-25 years, D. 30-40 years', 'role': 'user'}, {'content': 'Answer: A \nExplanation: → Streptococcus pneumoniae is the leading cause of pneumonia, both lobar and bronchopneumonia.\n→ Pneumonia is common at the extreme of ages:\n\nChildren (especially >5 years of age)\nElderly (>60 - 65 years)\n\n→ Serotypes 6, 14, 18, 19 and 23 are responsible for most cases of pneumonia in children, while serotypes 1, 3, 4, 7, 8 and 12 cause pneumonia in adults.', 'role': 'assistant'}]