When kerosene oil is added to stagnant water, mosquitoes reduce because it interferes with the breathing of the larvae; option [C]. Kerosene forms a thin film on the water’s surface, which blocks the larvae’s access to air. Since mosquito larvae need to breathe air through a siphon at the water surface, the layer of kerosene prevents them from doing so effectively, leading to suffocation and mortality. This disruption of their respiratory process significantly impairs their ability to survive and develop into adult mosquitoes.

While kerosene does not directly poison the mosquitoes or drive them away, its presence alters the environment in a way that is inhospitable to mosquito larvae. By obstructing their access to essential air, kerosene effectively hinders their development and reproduction cycle. This method is often used as a non-toxic approach to mosquito control, as it targets the larvae rather than adult mosquitoes. Consequently, by reducing the mosquito population at the larval stage, it helps mitigate the risk of mosquito-borne diseases and discomfort caused by adult mosquitoes.