Compund (A) and (B) respectively are :

Compund (B) is:

Compund (B) is:

Compund (B) is:

Compund (B) is:

Compund (B) is:

Compund (B) is:

In the complex [Pt(py)_4][PtCl_4] , the oxidation numbers of Pt atom in former and latter part of the compund are respectively