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 grand rapid survey (1945) of water fluoridation, which city was used as control? \nSelect and explain. \nA. Kingston, B. Muskegon, C. Oakpark, D. Evanston', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]