In which one of the following instruments leather is not used?

Correct option is C

Correct Option: c)
Leather (skin or parchment) is used in the construction of membranophones (drums like tabla, pakhawaj) and also sometimes in certain string instruments as a covering on the resonator to modify the tone.
Information Booster:
· The Sursingar (also Sursringar) is a plucked string instrument, essentially a bass version of the Rabab or Sarod.
· Its soundboard (resonator) is made entirely of wood, not covered with leather.
· Therefore, leather is not used in its construction.
Additional Knowledge:
· The Israaj, Dilruba, and Sarod all have a skin (goat skin) covering on their main resonating chamber, which is essential for their distinctive warm and resonant tone.