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 Length of the proximal guide plane is of the enamel crown portion of the tooth from the marginal ridge cervically is: \nSelect and explain. \nA. 3-Jan, B. 3-Feb, C. 2-Jan, D. Entire length', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]