●In the vapour absorption system, the energy input is given in the form, of the heat

●While in vapour compression system, the energy input is given in the form of the mechanical works from the electric motor run by the electricity.

●Thus vapour absorption system works on the low grade thermal energy such as waste heat or solar energy

●Air cycle refrigeration works on the reverse Brayton or Joule cycle. Air is compressed and then heat removed. This air is than expanded to a lower temperature than before it was compressed. As compressor is used it too requires electricity

●The compressor an electric component of vapour compression cycle is replaced by absorbs generator in the absorption refrigerating system which does not requires electricity.

Hence, the correct option is (A).