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': 'White gold alloy predominantly is: \nSelect and explain. \nA. Gold added with palladium, B. Gold added with calcium, C. Gold with much of chromium, D. Gold with silver', 'role': 'user'}, {'content': 'Answer: A \nExplanation: These alloys were introduced as a cheaper alternative to gold alloys.\nIt is predominantly silver in composition. Palladium (at least 25%) is added to provide nobility and resistance to tarnish. They may or may not contain copper and gold. They are white in color.\nThe current trend is to avoid the display of metal. At the same time, increase in the platinum, palladium and silver content of modern alloys have resulted in whiter colored gold alloys. Thus, there are ‘yellow gold alloys’ and ‘white gold alloys’. The rise in gold prices has also led to the availability of alloys with low gold content. These are the ‘low golds’.\nRef: Mannapalli 3\xa0ed page no 273', 'role': 'assistant'}]