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': 'Fractured metal parts in an RPD are best joined by \nSelect and explain. \nA. Spot welding, B. Brazing, C. Laser welding, D. Electric soldering', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]