How many of the following are paramagnetic species having ${\mu }_{\text{spin }}$ (Magnetic moment) $2.8 \mathrm{BM}$ ?

${\mathrm{N}}_2,{\mathrm{O}}_2,{\mathrm{B}}_2,{\mathrm{C}}_2,{\mathrm{C}}_2^{2+},{\mathrm{N}}_2^{2-},{\mathrm{F}}_2,{\mathrm{O}}_2^{-},{\mathrm{Li}}_2^{+},{\mathrm{B}}_2^{-}$

Four paramagnetic species having ${\mu }_{\text{spin }}$ (Magnetic moment) 2.8 BM.

${\mathrm{N}}_2,{\mathrm{O}}_2,{\mathrm{B}}_2,{\mathrm{C}}_2,{\mathrm{C}}_2^{2+},{\mathrm{N}}_2^{2-},{\mathrm{F}}_2,{\mathrm{O}}_2^{-},{\mathrm{Li}}_2^{+},{\mathrm{B}}_2^{-}$

Species having 2 unpaired $e^{-}\to {\mathrm{O}}_2,{\mathrm{B}}_2,{\mathrm{N}}_2^{2-},{\mathrm{C}}_2^{2+}$

Hence correct option is A.