$HgCl_2$ and $I_2$ both when dissolved in water containing $I^{-}$ ions the pair of species formed is :

Question

$\begin{array}{1 1} (1)Hgl_2,I_3^{-} \\ (2) HgI_2,I^{-} \\ (3) HgI_4^{2-},I_3^{-} \\ (4) Hg_2I_2,I^{-} \end{array}$