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 type of gold alloy used in fixed partial dentures is: \nSelect and explain. \nA. Soft gold, B. Hard gold, C. Medium gold, D. Extra hard gold', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]