is a reducing agent in the overall reaction for photosynthesis?

Hydrogen ion [H]

Explanation:

overall reaction of photosynthesis is given in this two steps equation . 

Firstly, oxygen in water is oxidized by the light energy:

            2H2O          →           O2 + 4 [H.]                   

 [H.] reduces the carbon in CO2:

            4 [H.] + CO2          →           (CH2O) + H2O                                    

This reaction occurs together, to yeild overall reaction

CO2 + H2O       →      (CH2O) +O2

Where [H.], the overall reducing agent

im pretty sure its b

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.