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
In electralloy calcium is alloyed with gold, as calcium: 
Select and explain. 
A. Increase whiteness of the alloy, B. Increase corrosion resistance, C. Increases the strength., D. Increase opacity.
C: Increases the strength.
Answer: C: Increases the strength. 
Explanation: The electrolytic precipitate of gold is alloyed with 0.1% calcium.
Calcium increases the strength by dispersion strengthening