Which of the following has maximum freezing point for 1 molal solution, assuming equal ionisation in each case?

Question

$\begin{array}{1 1}(a)\;[Fe(H_2O)_3Cl_3].3H_2O\\(b)\;[Fe(H_2O)_4Cl_2].Cl.2H_2O\\(c)\;[Fe(H_2O)_5Cl].Cl_2.H_2O\\(d)\;[Fe(H_2O)_6].Cl_3\end{array}$