The graph illustrates the concentration of oxygen in the air spaces of a green leaf of a plant over a $12$-hour interval. Which statement is correct about carbon dioxide in the air spaces during time X?
- ACarbon dioxide is being produced because the rate of photosynthesis is greater than the rate of respiration.
- BCarbon dioxide is being produced because the rate of respiration is greater than the rate of photosynthesis.
- CCarbon dioxide is being used because the rate of photosynthesis is greater than the rate of respiration.
- DCarbon dioxide is being used because the rate of respiration is greater than the rate of photosynthesis.