The two forms of oxygen found in the atmosphere are
Oxygen is present in our atmosphere in the form of a diatomic molecule. It is present in troposphere in approximately 20.93 (percentage of volume). Oxygen is required by the living beings for respiration and burning (combustion) of materials. Its percentage in air is balanced by photosynthesis.
Ozone is an allotrope of oxygen present in significant amount in stratosphere. It is a triatomic blue gas with pungent odour. The ozone is highly important as it filters out high energy UV radiations from the sun. These radiations split ozone into molecular and atomic oxygen.
The correct option is C.