A、[Cr(NH<sub>3sub>)<sub>4sub>(H<sub>2sub>O)<sub>2sub>]Cl<sub>3sub> B、[Cr(NH<sub>3sub>)<sub>4sub>Cl<sub>2sub>]Cl C、[Cr(NH<sub>3sub>)<sub>4sub>(H<sub>2sub>O)Cl]Cl<sub>2sub> D、[Cr(NH<sub>3sub>)<sub>3sub>Cl<sub>3sub>]