The numerical
designation of air as refrigerant is :
प्रशीतक के रूप में वायु का संख्यात्मक पदनाम है:
729
744
718
717
729
Air is an
inorganic refrigerant and the nomenclature for inorganic refrigerant is as
stated below, 
So, numerical
designation for air is R–729
Hence, the
correct option is (A).
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