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 occlusal clearance for a complete cast crown is: \nSelect and explain. \nA. 0.5 m, B. 1.5 mm, C. 2 m, D. 2.5 mm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]