Ultra-violet radiation from sun light causes the reaction that produce which of the following?

1. A

   CO

   Carbon monoxide is produced mainly by incomplete combustion of carbon fuels, not by ultraviolet sunlight acting on the upper air. UV chemistry is not the source of CO in the classic school pairing. This option is not the key.

2. B

   SO

   Sulphur oxides come from burning sulphur-bearing fuels and from volcanoes. They are not the product of the ultraviolet–oxygen reaction in the stratosphere. This option is therefore wrong.

3. C

   Ultraviolet radiation from the Sun photolyses molecular oxygen in the stratosphere; the free oxygen atoms combine with O2 to form ozone. That is the reaction the question points to. Ozone is therefore the product named as the official key.

4. D

   Fluorides

   Fluorides in the environment come from minerals, industry and some water sources, not from sunlight-driven ultraviolet reactions in the air. This option is not the key.

Summary. Official key is (c) Ozone. Solar ultraviolet splits oxygen molecules; the fragments rebuild as ozone, which then absorbs further ultraviolet. Carbon monoxide and sulphur oxides are combustion or volcanic products, not this photochemical path. Fluorides are unrelated to the UV–oxygen cycle. Only ozone is produced by that sunlight reaction among the given choices.