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
3rd generation of amalgam contains: 
Select and explain. 
A. Ag+Sn, B. Ag+Sn+Zn+Cu, C. Ag-Sn+Ag-Cu, D. Alloy+Indium
C: Ag-Sn+Ag-Cu
Answer: C: Ag-Sn+Ag-Cu 
Explanation: Generations of Amalgams