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': 'Functional Cusp Bevel is given for: \nSelect and explain. \nA. Marginal integrity, B. Structural durability, C. Retention and resistance form, D. To improve the geometry of tooth surface', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]