Which of following chemical cause thinning of layer P?

Chlorofluorocarbon (CFC) is composed of carbon, fluorine, and chlorine. CFCs are also called freons. CFCs, once released into the atmosphere, accumulate in the stratosphere, where they react with ozone ($O_3$) and contribute to the depletion of the ozone layer by breaking the O${}_3$ into O${}_2$ and free oxygen. Stratospheric ozone shields life on earth from the harmful effects of the sun's ultraviolet radiation; even a relatively small decrease in the stratospheric ozone concentration can result in an increased incidence of skin cancer in humans and genetic damage in many organisms.