Which of the following best describes a "broad-spectrum" pesticide?

A "broad-spectrum" pesticide is one that affects a wide range of pests, making choice C the best description. These pesticides are formulated to control multiple types of insects or other pests, rather than being limited to a single species. This broad effectiveness can be beneficial in situations where numerous pest species are present, allowing for comprehensive pest management with a single application.

In contrast, a pesticide that targets only one specific pest species is characterized as selective, which is not the case with broad-spectrum pesticides. A narrow range of effectiveness refers to pesticides that only work on a limited number of pests, which also does not apply to broad-spectrum types. Additionally, the location of use, such as indoors or outdoors, does not define whether a pesticide is broad-spectrum; rather, it pertains to the spectrum of pests it can control. Thus, the focus of broad-spectrum pesticides is on their ability to impact a wide variety of pest species.