Answer: Option B
Step-by-step explanation:
The product of respiration is used during the process of photosynthesis. The process by which green plants make food by the help of carbon dioxide, water in the presence of sunlight to get converted into glucose.
The carbon dioxide is produced in the environment by the animals and human beings as a by-product of cellular respiration.
So, the conclusion is that the reactant that is used in the process of photosynthesis is used by the plants.
Hence, the correct answer is option B