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': '18-8 Stainless steel orthodontic wire has: \nSelect and explain. \nA. 18% Nickel 8% Chromium, B. 18% Chromium 8% Nickel, C. 18% Chromium 8% Cobalt, D. 18% carbon 8% Iron', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]