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: Social & Preventive Medicine
Nalgonda Technique for defluoridation of water does not include addition of? 
Select and explain. 
A. Line, B. Alum, C. Bleaching powder, D. Barium sulfate
D: Barium sulfate
Answer: D: Barium sulfate 
Explanation: Nalgonda Technique involves addition of

Lime
Alum
Bleaching powder