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 fluoride agent used in dentifrices are \nSelect and explain. \nA. Sodium monofluoro phosphate, B. Amine fluoride, C. Sodium fluoride in organic base, D. Sodium fluoride in orthophosphoric acid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]