The enthalpies of vombustion of formaldehyde and paraformaldehyde (a ploymer of formaldehyde) arae -134 and -732 kcal/mol respectively .The enthalpy of polymerisation per mole of paraformaldehtde is -72 kcal the molecular formula of paraformaldehyde is:
A. `CH_(2)O`
B. `C_(6)H_(12)O_(6)`
C. `c_(12)H_(22)O_(11)`
D. `C_(3)H_(6)O_(3)`