Answer;
D. Formation of NADPH
Explanation;
During the process of photosynthesis light is converted to chemical energy.
During stage 1, Excited electrons that leave the chlorophyll pigments in stage 1 are used. Excited electrons are passed through proteins in the thylakoid membrane like a ball being passed from person to person. H2o molecules split and turn into H+ molecules and O2 gas, then pigments take the electrons from the split water molecules and release O2 into the atmosphere.
During stage 2; electrons from 1st cluster pump H+ ions into the thylakoid membrane through the hydrogen ion pump (protein membrane. Higher concentration of H+ ions inside the thylakoid membrane compared to outside. H+ ions diffuse out of the thylakoid throught the ATP synthase (enzyme in membrane). ATP synthase catalyzes the reaction ADP + P ---->ATP.
Stage 2; Excited electrons + H+ ions + NADP+= NADPH