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': 'Biocompatibility is best for: \nSelect and explain. \nA. Beta-titanium, B. Stainless steel, C. Nitinol, D. Base metal alloys', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]