GMAT Sentence Correction (SC) | During the process of photosynthesis, some of the light

During the process of photosynthesis, some of the light energy absorbed by chlorophylls is stored in the form of adenosine triphosphate (ATP); the rest is used for the removal of the electrons in water,to then be used in the reactions that turn carbon dioxide into organic compounds.
A) to then be used in the reactions that turn carbon dioxide into organic compounds
B) which are then used in the reactions that turn carbon dioxide into organic compounds
C) which are then used in the