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': 'Titanium casting is done with \nSelect and explain. \nA. Laser, B. Oven, C. Gas torch, D. Arc Melting with an argon atmosphere', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]