Final answer:
Photosynthesis requires carbon dioxide (CO2), water (H2O), and sunlight energy as reactants to produce glucose and oxygen.
Step-by-step explanation:
The reactants involved in photosynthesis are carbon dioxide (CO2), water (H2O), and sunlight energy. These components are necessary for the photosynthetic process that takes place in the chloroplasts of plant cells. The overall chemical equation representing photosynthesis is 6CO2 + 6H2O + sunlight energy → C6H12O6 + 6O2. Therefore, the correct answer to the question is B. H2O and CO2 and sunlight energy.