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 ideal ratio of pin in pin restoration between dentin and exposed surface of pin is: 
Select and explain. 
A. 3:01, B. 2:01, C. 1:01, D. 1:02
B: 2:01
Answer: B: 2:01 
Explanation: None