Match each of the diatomic molecules in Column I with its...

- A. $B_2$ : Has two unpaired electrons, making it p. Paramagnetic. The close energy levels of $2 s$ and $2 p$ orbitals lead to ($\mathrm{t.s - p}$) mixing. - B. (\boldsymbol{N}_{\mathrm{2}}) : Has a bond order of ($\mathrm{3}$), so its bond order is ($\mathrm{s}$). ($\mathrm{\geq 2}$). It also has ($\mathrm{t . s - p}$) mixing and can gain electrons, so it r. Undergoes reduction. - C. $O_2$ : Has two unpaired electrons, making it p. Paramagnetic. Its bond order is 2 , so it's ($\mathrm{s}$). (\geq) 2. With electrons in antibonding orbitals, it can lose electrons, thus q. Undergoing oxidation. - D. $O_2^{-}$: Has one unpaired electron, making it p. Paramagnetic. It can both gain and lose electrons, so it q. Undergoes oxidation and r. Undergoes reduction. The correct option is (3).