Analysing the given parts
(A) Acid rain is perfectly matched with CO2 and SO2. As they fall to the ground from the atmosphere in wet or dry forms.
(B)Photochemical Smog is perfectly matched with unsaturated hydrocarbons and SO2.
(C)Combination with haemoglobin is perfectly matched with 𝐶𝑂. 𝐶𝑂 combined with haemoglobin gives poisonous carboxy hemoglobin which does not allow oxygen to bind again on it.
(D)Depletion of ozone layer is perfectly matched with CHCl2−CHF2
From the above analysis we can conclude that the correct match will be:
(A)→iii,iv;(B)→iv,v;(C)→ii;(D)→i