The correct answer is C. phosphates.
Detergent is a cleaning agent that is used to remove dirt, grease, and other impurities from surfaces. It is made up of a number of different chemicals, including surfactants, which are responsible for its cleaning action. Surfactants are molecules that have both water-loving and oil-loving ends. When they are added to water, they form micelles, which are tiny spheres with the water-loving ends facing out and the oil-loving ends facing in. This allows the detergent to surround and remove dirt and grease from surfaces.
Detergent also contains phosphates, which are used to soften water. Phosphates are a type of nutrient that can cause nutrient enrichment in water bodies. When detergents are washed down the drain, the phosphates they contain can enter waterways. These phosphates can then stimulate the growth of algae, which can lead to a number of problems, including the depletion of oxygen in the water, the death of fish and other aquatic life, and the production of toxins that can harm humans and animals.
Carbonates, nitrates, and silicates are also nutrients that can cause nutrient enrichment in water bodies. However, they are not typically found in detergents in high enough concentrations to cause problems.
In conclusion, the influx of domestic sewage containing detergents cause nutrient enrichment in water bodies due to the presence of phosphates.