Aerobic biological oxidation ponds used for the purification of polluted water__________________?

Aerobic biological oxidation ponds used for the purification of polluted water__________________?

A. Destroys/removes pathogen from the sewage
B. Is not very effective for non-biodegradable substances (e.g. ABS) containing effluents
C. Destroys/removes pathogen much more effectively if the sewage is chlorinated
D. All A., B. & C.