For 1 molal aqueous solution of the following compounds, which one will show the highest freezing point ?

Question

( A ) $[Co(H_2O)_6]Cl_3$
( B ) $[Co(H_2O)_3Cl_3].3H_2O$
( C ) $[Co(H_2O)_5Cl]Cl_2.H_2O$
( D ) $[Co(H_2O)_4Cl_2]Cl.2H_2O$