The correct answer is option C, A food web
A food web represents the hierarchical order of feeding in a set of organisms with in a given ecosystem. It also represents the transfer of food energy from trophic level of food web to other trophic level. Basically if a food web if represented as a pyramid, the base position will be occupied the producers which trap the solar energy to produce food. At each trophic level 10% of the energy of its previous trophic level is retained while rest all is released. The entire food web is basically a web of energy and is very essential for the survival of the living beings with in an ecosystem.