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': 'Recommended dosage of fluoride mouth rinse for 12-14 year old is \nSelect and explain. \nA. 10 ml 0.2% NaF twice daily, B. 10 ml 0.2% NaF once daily, C. 10 ml 0.2% NaF twice monthly, D. 10 ml 0.2% NaF once monthly', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]