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': 'Chromium added to steel does not \nSelect and explain. \nA. Increase hardness, B. Increase tensile strength, C. Increase corrosion resistance, D. Decrease elastic limit', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Chromium forms a very thin, transparent, adherent layer of Cr2O3 through a process called passivation, which provides a barrier to diffusion of oxygen and other corrosive species and it prevents further corrosion of the underlying alloy.\nRef: Phillip’s 12th edition page 127.', 'role': 'assistant'}]