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
Marginal leakage related to temperature change occurs to the greatest extent with: 
Select and explain. 
A. Amalgam alloy, B. Unfilled resin, C. Composite resin, D. Direct filling gold
B: Unfilled resin
Answer: B: Unfilled resin 
Explanation: None