Answer:
C. Application of toxic fertilizers to crops
Step-by-step explanation:
Water pollution is defined as the contamination of water due to several human activities. Several causes of water pollution include use of fertlizers, construction of turbine, industrial waste, and sewage dumping.
Use of toxic fertizers directly affects the loss of water quality as fertilizers and pesticides are made up of chemicals such as phosphate and ammonia. The fertilizers and pesticides precipitate through the soil and mix with ground water that directly affect the quality of water. Residues of chemicals mix with river water due to flooding, excess irrigation, heavy rainfall and enter in the food chain. These chemicals are then have lethal effect in living organisms.
Hence, the correct answer is C.