Total number of molecules/species from following which will be paramagnetic is ____. O_2, O_2^+, O_2^-, NO, NO_2, CO, K_2[ NiCl_4],[ Co ( NH_3)_6]…

Total number of molecules/species from following which will be paramagnetic is $\displaystyle \_\_\_\_$. $$\mathrm{O}_2, \mathrm{O}_2^{+}, \mathrm{O}_2^{-}, \mathrm{NO}, \mathrm{NO}_2, \mathrm{CO}, \mathrm{~K}_2\left[\mathrm{NiCl}_4\right],\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3, \mathrm{~K}_2\left[\mathrm{Ni}(\mathrm{CN})_4\right] $$