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 main reason behind heating the powdered gold is to ensure complete elimination of: \nSelect and explain. \nA. Wax, B. Oxide layer, C. Other contaminants, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Powdered gold must be heated in a flame to ensure the complete elimination of the wax. When heating in bulk on a tray, an excessive amount of gold should be avoided because of\xa0the\xa0difficulties\xa0that\xa0prolonged\xa0and\xa0repeated\xa0heating\xa0can create. Care should be taken to handle pieces with stainless steel wire points or similar instruments that will not contaminate the gold.\nRef:Phillip’s Science of Dental Materials ed 12 pg 414', 'role': 'assistant'}]