The evaporator changes the low pressure liquid refrigerant from the expansion valve into

high pressure liquid refrigerant
low pressure liquid and vapour refrigerant
low pressure vapour refrigerant
none of these
✅ The correct answer is option C.

Environmental protection agencies advice against the use of chloro-fluoro-carbon refrigerants since

these react with water vapour and cause acid rain
these react with plants and cause green-house effect
these react with oxygen and cause its depletion
these react with ozone
✅ The correct answer is option D.