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
During cobalt chromium crown reconstruction, temperature of soldering torch suddenly increases. In such case, which of the following property will change? 
Select and explain. 
A. Yield strength decreases and percent elongation increases, B. Yield strength and percent elongation both increases, C. Yield strength increases and percent elongation decreases, D. Yield strength and percent elongation both decreases
D: Yield strength and percent elongation both decreases
Answer: D: Yield strength and percent elongation both decreases 
Explanation: Heat treatments of cobalt-based alloys reduce both the yield strength and elongation. If for any reason, some soldering or welding must be performed on these removable dental prostheses, the lowest possible temperature should be used with the shortest possible heating time.
Ref: Craig’s 14th edition page 194.