The correct answer is: A. Agricultural and sewage water.
Eutrophication is the process by which a body of water becomes enriched with nutrients, particularly phosphorus and nitrogen. This can lead to an increase in the growth of algae and other aquatic plants, which can eventually choke out other aquatic life.
Agricultural and sewage water are two of the main sources of nutrients that contribute to eutrophication. When these waters are not properly treated, they can release large amounts of nutrients into waterways. These nutrients can then stimulate the growth of algae and other aquatic plants.
Vehicle exhaust is not a major source of nutrients that contribute to eutrophication. However, it can contribute to air pollution, which can have other negative impacts on the environment.
Pesticides are not a major source of nutrients that contribute to eutrophication. However, they can be harmful to aquatic life if they are not used properly.
Industrial effluents can contain a variety of pollutants, including nutrients. If these effluents are not properly treated, they can release large amounts of nutrients into waterways. These nutrients can then stimulate the growth of algae and other aquatic plants.
In conclusion, the correct answer is: A. Agricultural and sewage water.