Which of the following is not paramagnetic?

What is the effect of the following processes on the bond order in $N_{2}$ and $O_{2}$?
$(A)$ $N_{2} \to N_{2}^{+} + e^{-}$
$(B)$ $O_{2} \to O_{2}^{+} + e^{-}$

$He_{2}$ molecule is not possible. Explain.

Which of the following is paramagnetic?

Arrange the following in the increasing order of their bond order: $O_{2}, O_{2}^{+}, O_{2}^{-}, O_{2}^{2-}$

Consider the following changes $I$ and $II$ as shown in the figure. The correct statements about these changes $(I)$ and $(II)$ in accordance with $MO$ theory are:
$A$) In $(I)$ bond order increases by $0.5$ from the existing value.
$B$) In $(II)$ bond order decreases by $0.5$ from the existing value.
$C$) In both $(I)$ and $(II)$ magnetic property is changed.
$D$) In both $(I)$ and $(II)$ magnetic property is not changed.