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': 'The final polish of a cast gold alloy to achieve a smooth polished surface is done by \nSelect and explain. \nA. Pickling, B. electropolishing, C. sand blasting, D. rouge', 'role': 'user'}, {'content': 'Answer: D \nExplanation: None', 'role': 'assistant'}]