Explanation:
The correct answer is option 'D', the Carius method.

The Carius method is a technique used for the estimation of halogens (chlorine, bromine, and iodine) and sulfur in organic compounds. This method involves heating a known mass of the organic compound with fuming nitric acid in the presence of silver nitrate.

Here is a detailed explanation of each option and why option 'D' is the correct answer:

a) Feulgen method:
The Feulgen method is a technique used to stain DNA in cells for microscopic examination. It involves treating the cells with hydrochloric acid, followed by treatment with Schiff's reagent and sulfurous acid. This method is not related to the estimation of organic compounds.

b) Dumas method:
The Dumas method is a technique used to determine the molecular weight of volatile substances. It involves heating a known mass of the substance in a combustion tube and collecting the resulting gases. The gases are then analyzed to determine the molecular weight of the substance. This method is not related to the estimation of organic compounds.

c) Kjeldahl method:
The Kjeldahl method is a technique used to determine the nitrogen content in organic compounds, particularly in proteins. It involves digestion of the compound with concentrated sulfuric acid and potassium sulfate, which converts the nitrogen to ammonium sulfate. The ammonium sulfate is then treated with sodium hydroxide and distilled to collect the ammonia, which is titrated to determine the nitrogen content. This method is not related to the estimation of organic compounds using fuming nitric acid and silver nitrate.

d) Carius method:
The Carius method is a technique used to estimate the halogens (chlorine, bromine, and iodine) and sulfur content in organic compounds. It involves heating a known mass of the organic compound with fuming nitric acid in the presence of silver nitrate. The halogens and sulfur present in the compound react with the fuming nitric acid to form their respective silver salts. These silver salts are then filtered, washed, and weighed to determine their mass, which is used to calculate the percentage of halogens and sulfur in the compound.

Therefore, the correct answer is option 'D' - Carius method.