$CaOCl_2+ H_2O \longrightarrow Ca(OH)_2+X;\;X+CH_3CHO \longrightarrow Y \; ; Y+ Ca(OH)_2 \longrightarrow CHCL_3.$ What is Y?

Question

\[\begin {array} {1 1} (a)\;CH_3CH(OH)_2& \quad (b)\;CH_2Cl_2 \\ (c)\;CCl_3CHO & \quad (d)\;CCl_3COCH_3 \end {array}\]