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': 'In dentifrices, concentration of fluoride is: \nSelect and explain. \nA. 800 ppm, B. 2000 ppm, C. 1000 ppm, D. 600 ppm', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Topical fluoride products can be divided into 2 broad categories:\n\nProfessionally applied products\n\tProfessionally applied fluoride products are those medicaments typically dispensed by dental professionals in the dental office and usually involve the use of high fluoride concentration products, ranging from 5000 and 19000 ppm, which is equivalent to 5-19 mgF/ml.\nSelf-applied products\n\tSelf-applied fluoride products are usually bought and dispensed by the individual patient, but at the recommendation of dental personnel. These products include\xa0fluoride dentifrices, mouthrinses and gels and typically are low fluoride concentration products ranging from 200 to 1000 ppm or 0.2 -1.0 mg fluoride/ml.\n\nEssentials of preventive and community dentistry\nSoben Peter\n5th edition\npage no. 252', 'role': 'assistant'}]