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: Dental
[{'content': 'The most common cause of inflammation of gingiva in\nchildren is: \nSelect and explain. \nA. Juvenile periodontitis, B. Acute herpetic gingivostomatitis, C. Diphtheria, D. Leukemia', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]