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': 'In type II gold alloys,  __________  Karat gold is used. \nSelect and explain. \nA. 20 K, B. 24 K, C. 18 K, D. 10 K', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Types of dental casting gold alloys\xa0\nDental casting\xa0gold alloys\xa0\n\nHigh carat gold alloy (gold alloys by type) (gold-silver-copper alloys)\xa0\n\tType 1\xa0-\xa022K gold alloy\n\tType 2 -\xa020K gold alloy\n\tType 3 -\xa018K gold alloy\n\tType 4 -\xa0Gold platinum alloy\n\t\xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa0 \xa014K gold alloy\xa0\nMedium carat gold alloy\nLow carat gold alloy\xa0\n\nAdvances in metallic biomaterials processing & applications pg 262', 'role': 'assistant'}]