The cation is sodium ion and the anion is the complex ion. The ligands present are ammine, bromo, chloro, and nitro$-N$. Here $N$ represents that the nitro group coordinates through the $N$ atom. The names of the ligands are written in the alphabetical order. The oxidation state of platinum is $+2$. The oxidation state is written in Roman numerals inside the parenthesis.
$(A)$ $\mathrm{Ni}(\mathrm{CO})_{4}$
$(B)$ $\left[\mathrm{Ni}\left(\mathrm{H}_{2} \mathrm{O}\right)_{6}\right] \mathrm{Cl}_{2}$
$(C)$ $\mathrm{Na}_{2}\left[\mathrm{Ni}(\mathrm{CN})_{4}\right]$
$(D)$ $\mathrm{PdCl}_{2}\left(\mathrm{PPh}_{3}\right)_{2}$