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 main difference between composite and amalgam as restorative material is: \nSelect and explain. \nA. Occlusal wear, B. Durability, C. Retention, D. Manipulation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]