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 finished and polished amalgam will: 
Select and explain. 
A. Tarnish with time, B. Not tarnish and corrode easily, C. Show secondary caries, D. Do none of the above
B: Not tarnish and corrode easily
Answer: B: Not tarnish and corrode easily 
Explanation: None