The sum of the oxidation state and the coordination number of the central metal atom is maximum for which of the following complexes?

The molecular formula of tetraammineaquachloridocobalt$(III)$ chloride is . . . . . . .

The correct $IUPAC$ name of $[Pt(NH_3)_4Cl_2] [PtCl_4]$ is:

The $IUPAC$ name of $[Pt(NH_3)_2Cl(NO_2)]$ is:

The oxidation states of iron atoms in compounds $(A),$ $(B)$ and $(C),$ respectively,are $x,$ $y$ and $z.$ The sum of $x, y$ and $z$ is........
$(A)$ $Na_4[Fe(CN)_5(NOS)]$
$(B)$ $Na_4[FeO_4]$
$(C)$ $[Fe_2(CO)_9]$

The $IUPAC$ name of $[Co(NH_3)_3(NO_2)_3]$ is