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.
(Painter : Gallery), (Actor : Stage), (Mason : Wall), (Farmer : Field), (Worker : Factory)
Clearly, the answer is (c).
In all other pairs, second is the place where the first works.