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': 'Amount\tof\treduction\tin\tdental\tcaries\tachieved\tby\ndentifrices is: \nSelect and explain. \nA. 20-35%, B. 35-40%, C. 40-50%, D. 50-60%', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]