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
Which of the following methods is used for deflouridation? 
Select and explain. 
A. Boiling, B. Nalgonda, C. Nalanda, D. None of the above
B: Nalgonda
Answer: B: Nalgonda 
Explanation: None