Answer: Option A. Light
Step-by-step explanation:
Photosynthesis is defined as the process by which plants make their own food in the presence of light and produces glucose by utilizing carbon dioxide and water.
During photosynthesis, the energy from sunlight is used and trapped by chloroplast which produces glucose from carbon dioxide and water. the glucose is further converted into pyruvate that releases ATP (adenosine triphosphate) and form oxygen.
Following is the equation that states photosynthesis in the presence of light:
carbon dioxide + water -------> glucose + oxygen
Hence, the light reaction supports formation of ATP and Oxygen during the process of photosynthesis.