Option 1 is incorrect because it includes all four compounds, while the correct answer specifies that only compounds 1 and 4 are used as fumigants.

Option 2 is incorrect because it includes compounds 2, 3, and 4, while the correct answer only includes compounds 1 and 4.

Option 3 is incorrect because it includes compounds 1, 2, and 3, while the correct answer only includes compounds 1 and 4.

The correct answer is option 4, which states that compounds 1 and 4 (Aluminium phosphide and Methyl bromide) are used as fumigants.

Fumigants are chemicals used to eliminate pests, such as insects, rodents, and microorganisms, from buildings, crops, or other areas. Aluminium phosphide and Methyl bromide are commonly used for this purpose.

Endosulfan and Malathion, which are included in options 2 and 3, are not used as fumigants. Endosulfan is an insecticide and acaricide, while Malathion is an insecticide and miticide.

In conclusion, the correct answer is option 4, which correctly identifies Aluminium phosphide and Methyl bromide