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
The main difference between composite and amalgam as restorative material is: 
Select and explain. 
A. Occlusal wear, B. Durability, C. Retention, D. Manipulation
A: Occlusal wear
Answer: A: Occlusal wear 
Explanation: None