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 American Dental Association (ADA) Specification No. 5 for Dental Casting Gold Alloys specifies : 
Select and explain. 
A. Minimum total gold-plus-platinum-metals -75 (wt%), B. Minimum total gold-plus-platinum-metals -25 (wt%), C. Minimum total gold-plus-platinum-metals -55 (wt%), D. Minimum total gold-plus-platinum-metals >75 (wt%)
A: Minimum total gold-plus-platinum-metals -75 (wt%)
Answer: A: Minimum total gold-plus-platinum-metals -75 (wt%) 
Explanation: The American Dental Association (ADA) Specification No.5 for Dental Casting Gold Alloys requires a minimum total gold-plus-platinum-metals content of 75 weight percent (wt%). 
Sturdevant operative dentistry 7th Edition, Page No:e94