What would happen if the electron transport system in the light-dependent reaction of photosynthesis was disabled for some reason?

here is the suggested answer, the other works too tho.

If the electron transport system did not work, electrons from PSII would not be transferred to PSI. Ferredoxin would then have no electrons to transfer to NADP+ so NADPH would not be produced. This would also affect the light-independent reaction of photosynthesis because NADPH is needed in this reaction.