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
ADA specification number for gypsum product is: 
Select and explain. 
A. 20, B. 25, C. 15, D. 7
B: 25
Answer: B: 25 
Explanation: ADA Specification No. 25 classifies five types of gypsum products, with the property requirement for each type.