Which of the following pairs of complexes are isomeric with each other but their aqueous solutions exhibit different molar conductivities?
(1) [PtCl2(NH3)4]Br2 and [PtBr2(NH3)4]Cl2
(2) [CoCl2(NH3)4]NO2 and [CoCl(NO2)(NH3)4]Cl
(3) [Co(NO2)(NH3)5]Cl2 and [Co(ONO)(NH3)5]Cl2
(4) [CoBr(NH3)5]SO4 and [Co(SO4)(NH3)5]Br