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 gold alloys used for casting contain at
least ________ percent of precious metal according
to ADA specification number 5: 
Select and explain. 
A. 55, B. 65, C. 75, D. 85
C: 75
Answer: C: 75 
Explanation: None