The right answer is NADP+.
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). The first protein of this type was isolated in 1962 from the anaerobic bacterium Clostridium pasteurianum. A chloroplast-specific 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 (EC 1.18.1.2) with FAD and a flavin group as cofactors:
2 ferredoxin- [Fe (2+) Fe (3+) S2 (-2)] + NADP (+) + H (+) ==> 2 ferredoxin- [Fe3 (+2) S2 (-2)] + NADPH .
