Which of following conditions lead to formation of ozone?

$\text{Correct option: }$ A

$\text{Solution: }$ 

$\text{Option (A) }$

$?$The energetic ultraviolet photon splits an oxygen molecule to form ozone molecules is known as photolysis. 

$?$It is assumed that the two resulting oxygen atoms will each form an ozone molecule.

$?$Ozone layer is responsible for protecting the earth's atmosphere from the harmful $?$Ultraviolet rays received from the sunlight.

$?$The thinning of the ozone layer is known as the ozone layer depletion that can result in the increase of the UV radiation reaching the earth's atmosphere.

$?$The major constituents responsible for ozone layer depletion are chlorofluorocarbons (CFCs) such as freons, halons, and other compounds.