The correct answer is: NADP+
During the light-dependent reactions of photosynthesis, four major protein complexes in the thylakoid membrane are involved in energy synthesis: Photosystem II (PSII), Cytochrome b6f complex, Photosystem I (PSI), and ATP synthase. All of them work together to create the final products ATP and NADPH. Reactions start when a chlorophyll a molecule within the PSII absorbs a photon, and an electron in this molecule attains a higher energy level (unstable state). Consequently the electron is transferred from one to another molecule which creates a chain of redox reactions also called electron transport chain.