The correct option is
C The products of one are used as the raw materials of the other
Photosynthesis is the process in which autotrophs such as green plants use carbon dioxide and water in presence of sunlight to synthesize nutrients such carbohydrates in the form of glucose and release oxygen.
In respiration, this glucose is oxidized in the presence of water to release carbon dioxide and generate energy. This carbon dioxide is released into the atmosphere and is taken by the plant during photosynthesis.
Hence, the products of one are used as the raw materials of the other.
Thus the correct answer is option C.