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
A highly polished surface on a metallic dental restoration aids considerably in the prevention of the: 
Select and explain. 
A. Dimensional change, B. Thermal conductivity, C. Warpage, D. Tarnish and corrosion
D: Tarnish and corrosion
Answer: D: Tarnish and corrosion 
Explanation: None