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': 'Passivating alloys are: \nSelect and explain. \nA. Cr, Al, Ti, B. Cr, Mo, Ti, C. Cr, Gold, Ti, D. Cr, Fe, Ti', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]