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': 'Who postulated that water fluoridation is associated with reduced tooth decay? \nSelect and explain. \nA. Dean, B. Murray, C. Horowitz, D. Knutson', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]