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
Method of choice for purification of highly polluted water on a large scale is 
Select and explain. 
A. Boiling, B. Super chlorination followed by dechlorination, C. Chlorination, D. Ultraviolet light treatment
B: Super chlorination followed by dechlorination
Answer: B: Super chlorination followed by dechlorination 
Explanation: None