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': 'Water fluoride concentration in areas with cold weather condition \nSelect and explain. \nA. More than 1 ppm, B. 1 ppm, C. Less than 0.7 ppm, D. 4 ppm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]