Answer:
Point C
Step-by-step explanation:
Oxygen is a by-product of photosynthesis. It is generated in the light stage. The rate of photosynthesis is affected by various factors. At point C, there is optimum amount of light and temperature thus more oxygen is produced.
The rate of photosynthesis increases as the light intensity increases. Most plants require red and blue wave-lengths of light for photosynthesis. Photosynthesis is a processs that is controlled by enzymes. Enzyme controlled reactions are affected by temperature. At dawn the rate of photosynthesis is low because temperatures are low. At dusk there is optimum temperature thus high oxygen rate due to increased rate of photosynthesis.