Allotropes of oxygen are

Allotropes are diverse variations of the same element with distinct properties.

Oxygen ($\mathrm{O}$) is a highly reactive element that does not exist as a single atom. Oxygen can bond to practically any other element, and if no other elements are available, it will bond to other oxygen atoms.

Allotropes of oxygen, such as the ${\mathrm{O}}_2,{\mathrm{O}}_3,{\mathrm{O}}_4$result of this process. The most frequent allotrope of oxygen is called dioxygen, ${\mathrm{O}}_2$. 

Dioxygen is vital for human beings as humans breathe in dioxygen. 

Another allotrope is Ozone, which is a somewhat blue-coloured molecule made up of three linked oxygen atoms. There is one more allotrope that is very rare and it is tetraoxygen (${\mathrm{O}}_4$).

Hence, the correct option is (C).