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': 'Which of the following is not an appropriate material for composite hand instruments? \nSelect and explain. \nA. Stainless steel, B. Teflon, C. Teflon coated metal, D. Nonmetallic', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]