What is the correct sequence of bond order for the given species?

The total number of electrons in all bonding molecular orbitals of $O_{2}^{2-}$ is $....$ (Round off to the Nearest Integer).

Match the following molecules/ions in List-$I$ with their respective bond orders in List-$II$:
| List-$I$ (Molecules/ions) | List-$II$ (Bond order) |
| :--- | :--- |
| $A. N_2^+$ | $I. 1.0$ |
| $B. CO$ | $II. 1.5$ |
| $C. O_2$ | $III. 2.0$ |
| $D. O_2^-$ | $IV. 2.5$ |
| | $V. 3.0$ |

How many among the given species have a bond order of $0.5$?
$H_2^{+}, He_2^{+}, He_2^{-}, B_2^{+}, F_2^{-}, Be_2^{2-}$

Select the correct set of statements regarding the molecular orbital theory of $O_2$:
$A$. Addition of an electron to $O_2$ decreases bond order.
$B$. Addition of an electron to $O_2$ increases bond order.
$C$. Removal of an electron from $O_2$ increases bond length.
$D$. Removal of an electron from $O_2$ decreases bond length.

The bond length of the species $O_2$,$O_2^+$ and $O_2^-$ are in the order of