In Choose odd pair of words type of questions, certain pairs of words are given out of which the words in all the pairs except one, bear a certain common relationship. The candidate is required to decipher this relationship and chose the pair in which the words are differently related, as the answer.
(Sprinkle : Pour), (Happiness : Merriment), (Mist : Fog), (Sad : Unhappy)
Clearly, the answer is (d).
In all other pairs, second is of higher intensity than the first while in (d), first is of higher intensity than the second.