Which of the following diatomic molecular species has only $\pi$ bonds according to Molecular Orbital Theory?

The pair of species with the same bond order is

Among the following species $N_{2}$,$N_{2}^{+}$,$N_{2}^{-}$,$N_{2}^{2-}$,$O_{2}$,$O_{2}^{+}$,$O_{2}^{-}$,$O_{2}^{2-}$,the number of species showing diamagnetism is:

Which of the following species has the highest bond energy?

The common features among the species $CN^{-}$,$CO$ and $NO^{+}$ are

Which one of the following pairs of species have the same bond order?