The answer is b, because all energy comes from the sun which then goes to the autotrophs( producers) who make there food, and then the omnivores eat the autotrophs and the carnivores eat the omnivores or anything that consists of meat.
Most of the producers are the plants and other autotrophic organisms that obtain their energy from the light energy of sun. These organisms use the light energy from sun to convert this energy into chemical energy of food by the process of photosynthesis. In the absence of sunlight energy photosynthesis will not occur. The ingredients like water and carbon dioxide are used to produce oxygen and carbohydrates in the presence of sunlight.
