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': 'Chamfer finish line in an anterior three quarter crown mainly imparts \nSelect and explain. \nA. Structural durability, B. Retention and Resistance, C. Periodontal preservation, D. None of the above', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]