Find out the number of species having paramagnetic nature as well as fractional bond order:

${\mathrm{B}}_2,\mathrm{NO},\mathrm{OF},{\mathrm{N}}_2,{\mathrm{KO}}_2,{\mathrm{K}}_2{\mathrm{O}}_2$

An atom in its magnetic paramagnetic state has one or more unpaired electrons. The magnetic dipole moments of these unpaired electrons cause them to be drawn by the magnetic field.

The number of species having paramagnetic nature as well as fractional bond order $\mathrm{NO}, \mathrm{OF},{ \mathrm{KO}}_2$.

This are total 3 in number. Thus, correct answer is 3.