The Ozone Layer forms naturally by
A. The interaction of CFC with oxygen
B. The interaction of UV radiations with oxygen
C. The interaction of IR radiation with oxygen
D. The interaction of oxygen with water vapour

Hint: Ozone is formed by the chemical reaction which occurs between sunlight and the oxygen molecules present in the atmosphere of the earth.

Complete answer:
Ozone Layer is present in the stratosphere. Ozone Layer is also known as Ozone shield. The Stratosphere is a layer of earth atmosphere. The Stratosphere is the region which absorbs high amounts of ultraviolet radiation coming from the Sun.
Due to this reason the stratosphere is the layer of atmosphere with highest concentration (of ozone) as compared to the other layers or the parts of the earth’s atmosphere.
The average concentration of ozone in the atmosphere of earth is 0.3 PPM full stop the thickness of the Ozone layer varies according to the Seasons and also the geographical regions.
The Ozone Layer is formed by the photochemical reaction or mechanism. This photochemical reactor formation of ozone was discovered by Sydney Chapman.
In the atmosphere the ozone layer is formed when the ultraviolet light from the sun collides or strikes with the oxygen molecules which contains two atoms of oxygen.
This collision results in the breakage or splitting of those oxygen molecules into singular atoms of oxygen. These atoms then fuse with the ordinary oxygen molecules and form an Ozone molecule containing 3 atoms of oxygen.
All the Ozone in the stratosphere has a long life but it is still not stable to fully stop this process of splitting of ozone again into one oxygen molecule and one oxygen atom is known as Ozone Oxygen cycle.

The correct answer is (B).

Note: The concentration of oxygen in the stratosphere is highest as compared to that in other layers of atmosphere but it is still less than the concentration of other gases in the stratosphere.