During the change of $O_2$ to $O_2^-$ ion,the electron adds to which one of the following orbitals?

Match the following:

Pair of species	Identical property
$A$. $B_2 \& O_2$	$P$. Bond order $= 2.5$
$B$. $Be_2 \& H_2^{2-}$	$Q$. Paramagnetic nature
$C$. $N_2^{+} \& N_2^{-}$	$R$. Diamagnetic nature
$D$. $O_2^{+} \& O_2^{-}$	$S$. Doesn't exist

Among the following,the molecule expected to be stabilized by anion formation is

During the change of $O_{2}$ to $O_{2}^{-}$,the incoming electron goes to the orbital:

The molecular orbital configuration of a diatomic molecule is
$\sigma 1s^2 \sigma^* 1s^2 \sigma 2s^2 \sigma^* 2s^2 \sigma 2p_x^2 \pi 2p_y^2 \pi 2p_z^2$
Its bond order is

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.