Under conditions of constant illumination, the compensation period for a whole aquarium would be of infinite length when

• A. The biomass of animals equals the biomass of plants
• B. The respiratory exchanges of the animals are equal to the photosynthetic exchanges of the plants
• C. The oxygen intake of the animals equals of oxygen output of photosynthesis
• D. The carbon dioxide output of the animals and plants equals to the photosynthetic intake of the plants