Schiff’s and Piria method is used for the estimation of:
(A).Nitrogen
(B).Sulphur
(C).Halogens
(D).oxygen

Hint: This method is used when a known amount of organic compound is fused with calcium oxide and sodium carbonate in the platinum or nickel crucible.

Complete answer:
In the Schiff’s and Piria method the product obtained is dissolved in excess of nitric acid and halogen is precipitated with silver nitrate. Halogens are estimated using the Schiff’s and Piria method.
In this method the accurately weigh organic compound is taken in a small crucible with a mixture of lime and sodium carbonate i.e. $Cao+N{{a}_{2}}C{{O}_{3}}$. It is then heated strongly and after that it is called and then dissolved in dilute nitric acid in a beaker.

Hence the correct answer is (C) i.e. Schiff’s and Piria method is used for the estimation of halogens.

Additional information:
Carius method is also used for the estimation of halogens.
In this method we use a known weight of organic compound which is heated with fuming nitric acid in the presence of silver nitrate in a glass tube which is hard. The carbon and hydrogen present in the compound are oxidized to carbon dioxide and water. And the halogens form silver halide.

Note:
The three main silver halides can be distinguished on the basis of their color. The precipitate form in silver chloride has white color, and in silver bromide a creamy colored precipitate is formed and a yellow color precipitate is formed in silver iodide. Silver chloride has the chemical formula of AgCl, silver bromide has the chemical formula of AgBr, and silver iodide has the chemical formula of AgI.