Which of the following is listed as an example of water pollution?

• A. Fresh water
• B. Sewage
• C. Wind
• D. Noise

Answer: (B)

The main idea here is recognizing what counts as a contaminant that pollutes a water body. Sewage is a classic example because it carries organic material, nutrients, and microbes into rivers, lakes, or oceans. This input can raise the biochemical oxygen demand, deplete dissolved oxygen, promote bacterial growth, and spread diseases, all of which degrade water quality and harm aquatic life and human health.

Fresh water by itself is just water and not a pollutant. Wind is a form of energy in the air, and noise is an auditory disturbance; neither is a contaminant that directly pollutes water. So the option that best represents water pollution is sewage.