Among the species ${\mathrm{CO}}_2\cdot {\mathrm{CH}}_3{\mathrm{COO}}^{-},\mathrm{CO},{\mathrm{CO}}_3^{2-}.$ $\mathrm{HCHO}$ which has the weakest carbon-oxygen bond

Among the given species. The bond dissociation of $\mathrm{C}-\mathrm{O}$ bond is minimum in case of ${\mathrm{CO}}_3^{2-}$by $\mathrm{C} - \mathrm{O}$ bond become more weaker in ${\mathrm{CO}}_3^{2-}$ or bond order of ${\mathrm{CO}}_3^{2-}$ (1.33) is minimum so the become weaker.