Rahul bought a sack of rice. He saw that there were a few stones present in it. He can utilise method to separate stones from the rice grains.

The correct option is A handpicking
Handpicking is a method used to remove unwanted particles which are easily identifiable, due to their different colour or size.
These impurities can be just picked out with hand and removed from the mixture.
The size of the stones is usually larger than that of rice. Hence, handpicking is preferred in this case.