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 crown preparation has a degree of convergence from gingival finish line towards occlusal is \nSelect and explain. \nA. 2° - 4°, B. 3° - 5°, C. 4° - 9°, D. 8° - 11°', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]