Photosynthesis is a redox reaction. this means that h2o is during the light reactions and co2 is during the calvin cycle.
a.
b.
c.
d.
e.

The correct answer is B. oxidized...reduced

Explanation:

In a redox reaction, oxidation and reduction occur in the same reaction by transferring an electron from one chemical species and accepting of electron form another chemical species.

Photosynthesis is a redox reaction in which the water molecule releases electrons and converts into Oxygen molecule during the light reaction and carbon dioxide is reduced to carbohydrate by using the electrons released by  NADPH molecules during Calvin cycle.

Therefore photosynthesis is a redox reaction in which H20 is oxidized and CO2 is reduced.