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.
(Blacksmith : Anvil), (Carpenter : Saw), (Barber : Scissor), (Goldsmith : Ornaments), (Sculptor : Chisel)
Clearly, the answer is (d).
In all other pairs, second is the tool used by the first.