Van't Hoff factor of $Hg_2Cl_2$ in its aqueous solution will be $(Hg_2cl_2)$ in its aqueour solution will be ($Hg_2cl_2$ is $80\%$ ionized in the solution

Question

$\begin{array}{1 1} 1.6 \\ 2.6 \\ 3.6 \\ 4.6 \end{array} $