Potassium hexa chloro platinate(IV) is

Question

$\begin{array}{1 1}(a)\;Pt_2[K(Cl)_6]&(b)\;K[Pt(Cl)_6]\\(c)\;K_2[Pt(Cl)_6]&(d)\;K_4[Pt(Cl)_6]\end{array}$