Which of the following species have maximum number of unpaired electrons

Among the following, the paramagnetic compound is

Give electron configuration, bond order magnetic property and energy diagram for Lithium $\left( {{\rm{L}}{{\rm{i}}_2}} \right)$ molecule. 

After understanding the assertion and reason, choose the correct option.
Assertion : In the bonding molecular orbital $(MO)$ of $H_2,$ electron density is increased between the nuclei.
Reason : The bonding $MO$ is ${\psi _A}\, + \,\,{\psi _{B,}}$ which shows destructive interference of the combining electron waves.

Among $\mathrm{H}_2, \mathrm{He}_2^{+}, \mathrm{Li}_2, \mathrm{Be}_2, \mathrm{~B}_2, \mathrm{C}_2, \mathrm{~N}_2, \mathrm{O}_2^{-}$, and $\mathrm{F}_2$, the number of diamagnetic species is (Atomic numbers: $\mathrm{H}=1, \mathrm{He}=2, \mathrm{Li}=3, \mathrm{Be}=4, \mathrm{~B}=5, \mathrm{C}=6, \mathrm{~N}=7, \mathrm{O}=8, \mathrm{~F}=9$ )

Number of paramagnetic oxides among the following given oxides is ..... .

$\mathrm{Li}_{2} \mathrm{O}, \mathrm{CaO}, \mathrm{Na}_{2} \mathrm{O}_{2}, \mathrm{KO}_{2}, \mathrm{MgO}$ and $\mathrm{K}_{2} \mathrm{O}$