The natural interconnections of food chain is :

The correct answer is Option (3) → Food web

Option (1) GFC — Incorrect. The grazing food chain (GFC) is one chain that starts from green plants. A food web is formed when such chains join.

Option (2) DFC — Incorrect. The detritus food chain (DFC) is one chain that starts from dead organic matter. It is linked to the GFC at some levels, but by itself it is not the web.

Option (3) Food web — Correct. Organisms of one chain also feed in others, so the chains join into a web.

Option (4) Biomass — Incorrect. Biomass is the mass of living organisms at a trophic level, not a network of feeding links.

NCERT Extract:
Energy Flow – “… Detritus food chain may be connected with the grazing food chain at some levels: some of the organisms of DFC are prey to the GFC animals, and in a natural ecosystem, some animals like cockroaches, crows, etc., are omnivores. These natural interconnection of food chains make it a food web.”