The right answer is Ferredoxin.
Ferredoxin is an iron-sulfur protein that effects electron transfer in a large number of redox reactions in cell metabolism through Fe-S clusters whose iron cations oscillate between +2 (ferrous) oxidation states. and +3 (ferric).
A particular chloroplast3 ferredoxin is involved in the cyclic and noncyclic photophosphorylation reactions of photosynthesis. In non-cyclic photophosphorylation, ferredoxin is the ultimate electron acceptor and reduces NADP + under the action of ferredoxin-NADP + reductase with FAD and a flavin group as cofactors.
