Correct option is C
The correct synonym of the given word is (c) Residue.
Silt: Fine sand, clay, or other material carried by running water and deposited as sediment. (कीचड़ या गाद)
Example: After the flood, the fields were covered in silt.
Residue: A small amount of something that remains after the main part has gone or been taken. (अवशेष)
Example: There was a sticky residue left on the plate.
Synonyms: deposit, sediment, residue, remains.
Antonyms: purity, cleanliness.
Meanings of all the other given options:
· (a) Cut: To divide or separate with a sharp tool (काटना)
· (b) Opening: An aperture or hole (छेद, खुला स्थान)
· (d) Incision: A surgical cut made in skin (चीर, चीरा)