The correct option is D A food chain
The feeding habit represents the nutrition relationship of different organisms in an ecosystem i.e., who eats whom. The flow of energy and matter in the form of food between different organisms is known as food chain. The food chain starts with autotrophs as they can prepare food on their own. The diagram represents a food chain where plants are the producers, the second position is occupied by grasshopper (heterotroph) which feeds on grass which in turn is eaten by frog (secondary consumers/ primary carnivore). The last position i.e., a tertiory position is occupied by top level heterotroph or secondary carnivore. Thus, the correct answer is option D.