The best answer is C - plant, animal, atmosphere.
During daylight hours, plants capture carbon dioxide from the atmosphere and use it to make carbohydrates which is stored as starch in the plant. Animals feed on the plants and extract the carbohydrates through their digestive system. The carbohydrates, namely glucose, are used by the animals for production of ATP through cellular respiration.
Cellar respiration in the animals produces carbon dioxide as a waste product. The carbon dioxide is released into the atmosphere, from where it is again captured by plants and the cycle is repeated.