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': 'Admixed high copper alloy powder contains \nSelect and explain. \nA. 9-20% copper, B. 13-20% copper, C. 9-30% copper, D. 13-30% copper', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]