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': 'Average daily intake of fluoride from all sources combined for adults and children is: \nSelect and explain. \nA. 2.0 to 2.2mg & 1.2mg, B. 1.2 to 2.0mg & 1.2mg, C. 2.2 to 2.4mg & 1.5mg, D. 2.6 to 2.8mg & 1.4mg', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]