This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
A type of teiary waste water treatment process is - 
Select and explain. 
A. Reverse osmosis, B. Sedimentation, C. Both, D. Neither
D: Neither
Answer: D: Neither 
Explanation: Sewage treatment Primary treatment : Physical treatment to remove solids (from the liquid) Secondary treatment : Bilogical treatment brought about by aerobic and anaerobic bacteria Teiary treatment : Improving fuher the quality of effluent (advanced waste treatment process), sludge (stabilisation and dewatering), assist sedimentation and sludge treatment (chemical treatment by the addition of coagulants) Ref: Park 25th edition Pgno : 800