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 function of copper added to 2nd generation amalgam is to: 
Select and explain. 
A. Increase plasticity, B. Increase strength, C. Decrease hardness, D. Increase brittleness
B: Increase strength
Answer: B: Increase strength 
Explanation: Copper was added up to 4% to decrease plasticity and to increase the hardness and strength of the alloy.
Reference: Marzouk Operative dentistry, pg-106