Answer:
The correct answer would be option D.
In any food web, the inorganic carbon from the atmosphere is incorporated into the organic matter by the process of photosynthesis.
Autotrophs perform photosynthesis and fix carbon obtained from carbon dioxide into the glucose or organic matter with the help of chlorophyll and in the presence of sunlight.
6 CO₂ + 6 H₂O → C₆H₁₂O₆ + 6 O₂