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
Nalgonda tech is used for 
Select and explain. 
A. Deflouridation, B. fluoridation, C. Purification of water, D. None
A: Deflouridation
Answer: A: Deflouridation 
Explanation: None