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': 'The percentage of copper in high copper alloy is: \nSelect and explain. \nA. 10-12%, B. 0 -6%, C. 13-30%, D. 20 -30%', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]