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 function of copper added to 2nd generation amalgam is to: \nSelect and explain. \nA. Increase plasticity, B. Increase strength, C. Decrease hardness, D. Increase brittleness', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Copper was added up to 4% to decrease plasticity and to increase the hardness and strength of the alloy.\nReference: Marzouk Operative dentistry, pg-106', 'role': 'assistant'}]