Answer: A) The use of freon and CFC spray propellants.
Chlorofluorocarbons (CFCs) are compounds that are used as propellents in the spray cans and in refrigerators. These are manufactured under the trade name of Freon. Freon is a CFC that contains fluoride as a main ingredient. These CFCs are released in the atmosphere and they accumulate in the stratospheric layer. The ozone layer is present in the stratosphere shields the Earth from the harmful ultraviolet rays. The CFC molecules breaks down by the ultra violet radiations. The released chlorine atoms or fluorine atoms reacts with the ozone molecules resulting in the removal of ozone layer from the stratosphere. This is called as ozone layer depletion.