Option 1 is incorrect because while both assertions are true, reason (R) is not the correct explanation for assertion (A). Ammonia and chlorofluorocarbon are indeed used as refrigerants, but not for the reasons outlined in (R).

Option 2 is also incorrect because although both A and R are true statements, R does not explain A. The reason industrial refrigeration systems prefer ammonia over chlorofluorocarbons is due to its superior thermodynamic qualities, not just its ability to be liquified at low pressures.

Option 3 is correct. Large cold storage plants do use ammonia while domestic refrigerators use chlorofluorocarbons in their cooling systems - that`s assertion (A), which is true. However, reason (R) is incorrect. While it`s true that Ammonia can be liquified at ambient temperatures at low pressures, it`s not the reason why it`s used as a refrigerant.

Option 4 is incorrect as assertion (A) is indeed true, large cold-storage plants do use ammonia as a refrigerant and domestic units use chlorofluorocarbons. The reason (R) though true, is not linked to this assertion.