Define non-point source pollutants.

Non-point source pollutants refer to contaminants that originate from widely spread or diffuse sources rather than a single identifiable point. This characteristic makes it challenging to directly control and manage these pollutants because they can come from various activities or land uses across a larger area.

For instance, agricultural runoff is a prime example of a non-point source pollutant. It includes fertilizers, pesticides, and sediment that wash off fields during rain events and enter surface waters. These pollutants are influenced by land practices and weather patterns, making their management complex.

The other options describe different types of pollutants or sources. Some focus on easily identifiable and controllable sources, while others refer to specific, localized emissions from facilities. However, the essence of non-point source pollution lies in its dispersed nature, which is why the definition captured in the correct choice is accurate.