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 fluoride concentration in 8% stannous fluoride, topical application, is \nSelect and explain. \nA. 1000 ppm, B. 9200 ppm, C. 19500 ppm, D. 12300 ppm', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]