The byproduct obtained from gut of fish:

Correct option is D

Fish gut (rich in collagen and connective tissue) can be processed to produce absorbable suture material similar to traditional “catgut.”
Source material: intestinal submucosa/collagen fibers.
Processing: cleaning → degreasing → sterilization → twisting into threads.
Properties: biodegradable, tensile strength adequate for soft-tissue closure, gradually absorbed by proteolytic enzymes.
Uses / Applications
Historically used in surgical procedures where absorbable stitches are required.
Useful in regions with limited access to synthetic absorbable sutures.
Notes on other options
Pearl essence: from fish scales (ground to produce pearlescent powder).
Caviar: fish roe (eggs).
Gum: plant-derived; not from fish.