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 maximum carbon content of steel used in dentistry is: \nSelect and explain. \nA. 19%, B. 2%, C. 1.70%, D. 4%', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Carbon steels can be described simply as iron-carbon binary alloys that contain less than\xa02.1% of carbon by weight.\nComposition (percent by weight) of three types of\xa0stainless steel by crystal structure of iron', 'role': 'assistant'}]