Select all the species in which the relevant bond has an average bond order of 1.5.

MO theory gives $\mathrm{O}{}_2{}^{-}$ bond order $(8-5)/2=1.5$. In $\mathrm{O}{}_3$ and $\mathrm{NO}{}_2{}^{-}$ one double plus one single bond are shared over two equivalent bonds: 1.5. In $\mathrm{CO}{}_3{}^{2-}$ one double plus two single bonds are shared over three, so the order is 4/3 = 1.33.