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
The rate of tarnish and corrosion of class II cast material having VHN 200 is 
Select and explain. 
A. 0%, B. 2 to 3%, C. 5 to 10%, D. <1%
A: 0%
Answer: A: 0% 
Explanation: None