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': 'The ideal ratio of pin in pin restoration between dentin and exposed surface of pin is: \nSelect and explain. \nA. 3:01, B. 2:01, C. 1:01, D. 1:02', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]