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: Pathology
Critical pH for initiation of caries: 
Select and explain. 
A. 4.3-4.5, B. 5.2-5.5, C. 4.9-5.1, D. 6.2-6.5
B: 5.2-5.5
Answer: B: 5.2-5.5 
Explanation: None