The first electron transport chain found between Photosystem II and Photosystem I is:

(a) used to capture small packets of energy to pump H* ions into the thylakoid space.
(b) used to reduce NADP* to NADPH as the primary electron carrier for photosynthesis.
(c) shunted to the regeneration of ribulose bisphosphate which is needed in the Calvin Cycle.
(d) passed to the final electron acceptor in the reaction center of Photosystem I known as P680.