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 role of antiflux in soldering stainless steel is: \nSelect and explain. \nA. To remove the chromium oxide layer, B. To increase the flow of solder, C. To reduce the fusion temperature of solder, D. To limit the flow of solder', 'role': 'user'}, {'content': 'Answer: D \nExplanation: A metal surface free of any contaminant, such as oxides, is\xa0essential for the molten solder to wet the substrate metals. The solder chosen must wet the metal at as low\xa0a contact angle as possible to ensure wetting of the joint area.\xa0To\xa0prevent\xa0flow\xa0of\xa0molten\xa0solder\xa0onto\xa0adjacent\xa0areas,\xa0an\xa0antiflux\xa0such as rouge mixed with chloroform or graphite can be\xa0painted\xa0on\xa0these\xa0areas\xa0before\xa0heating\xa0substrate\xa0metals.\xa0\n\nKey Concept:\xa0\nAntiflux — A substance such as graphite that prevents flow of molten solder on areas coated by the substance.\nReference: Phillips science of dental materials, 12th ed page no 367,389', 'role': 'assistant'}]