Which of the following is the most stable complex?

$AgCl$ dissolves in a solution of $NH_3$ but not in water because

$A$ solution containing $2.675 \ g$ of $CoCl_3 \cdot 6 NH_3$ (molar mass $= 267.5 \ g \ mol^{-1}$) is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of $AgNO_3$ to give $4.78 \ g$ of $AgCl$ (molar mass $= 143.5 \ g \ mol^{-1}$). The formula of the complex is
(At. mass of $Ag = 108 \ u$)

Considering the complexes $(i) K_2PtCl_6$,$(ii) PtCl_4 \cdot 2NH_3$,$(iii) PtCl_4 \cdot 3NH_3$,and $(iv) PtCl_4 \cdot 5NH_3$,the molar conductivities in aqueous solution follow the order (in $\Omega^{-1} \ cm^2 \ mol^{-1}$):

Which of the following complexes has the lowest molar conductivity in solution?

The solubility of $AgCl$ in $NH_4OH$ is due to the formation of: