The right option is; d. toxic chemicals used to control pest populations
Pesticides are best described as toxic chemicals used to control pest populations.
Pesticides are substances usually synthetic or biological which are used to control pests such as rodents, insects, microbes and unwanted plants (weeds). Pesticide includes herbicide, bactericide, fungicide, disinfectant, rodenticide, insecticides, sanitizer, insect repellent, and animal repellent. Pesticides are mainly used in agriculture, to kill pests that destroy crops and they are potentially toxic to humans and other organisms.