Which of the following methods can be used to separate a mixture of sand, naphthalene and salt?

Correct option is B

The Correct answer is Sublimation, decantation, evaporation.
Sublimation: Naphthalene is a substance that sublimates, that is, it directly changes from a solid to a gas state when heated. So by heating the mixture gently, you can separate naphthalene from the sand and salt.
Decantation: Now we are left with a mixture of sand and salt. By adding water to this mixture, the salt will dissolve. Then, you can pour off the saltwater (decantation), leaving the undissolved sand behind.
Evaporation: The saltwater solution now contains dissolved salt. By evaporating the water from this solution, you're left with the salt.
So by using the three methods in this combination (sublimation, decantation, evaporation), you can successfully separate a mixture of sand, naphthalene, and salt.