Correct Option: C

Water hyacinth (Eichhornia crassipes) is used for purifying not only domestic wastewater but also industrial wastewater. It can readily absorb, accumulate and concentrate heavy metals such as lead, cadmium, mercury and nickel. Other studies have evaluated the potential of water hyacinth to absorb various organic chemicals like phenols and toxaphene. Water hyacinth can remove even radioactive metals from industrial effluents, which is very difficult otherwise.