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

(1) CO, NO

(2) O_2-  , CN-

(3) CN- , NO+

(4) N+ , CN+

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

1. $O_2^{-},N{O}^{+}$

2. $C{N}^{-},CO$

3. $N_2, O_2^{-}$

2. CO, NO