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 best method to prevent initiation of caries in a four¬year-old child who has no accessibility to community water fluoridation is: \nSelect and explain. \nA. Brushing and flossing, B. 2.2% NaF tablet daily, C. 0.05% NaF mouthwash daily, D. 0.5% NaF toothpaste daily', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]