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 pH of APF gel is - 
Select and explain. 
A. 2.3, B. 3.2, C. 2.32, D. 1.23
A: 2.3
Answer: A: 2.3 
Explanation: None