Correct Option: C

Around the world, there is an increasing trend in areas of land, surface waters and groundwater affected by contamination from industrial, military and agricultural activities due to either ignorance, lack of vision, or carelessness. In the last three decades a special interest in the world is aroused by the potential of using the biological methods in the waste water treatment. Water hyacinth (Eichhornia crassipes) constitutes an important part of an aquatic ecosystem. Water hyacinth as a very promising plant with tremendous application in wastewater treatment is already proved. Water hyacinth is used to treat waste water from dairies, tanneries, sugar factories, pulp and paper industries, palm oil mills, distilleries, etc.