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
Oxidation pond is used in treatment ? 
Select and explain. 
A. Sewage, B. Effluent, C. Night soil, D. Sullage
A: Sewage
Answer: A: Sewage 
Explanation: Ans. is 'a' i.e.. Sew age