Correct option is D
Explanation-
Statement A: "Electron from P680 moves first to quinone and then to the pheophytin" - INCORRECT
In Photosystem II (PSII), P680 (a special chlorophyll a molecule) absorbs light energy and donates an electron.
The correct order of electron flow:
P680 → Pheophytin → Plastoquinone (Qa → Qb)
So, electron first moves to pheophytin, then to quinone, not the other way around.
Statement B: "P700 can receive electrons from plastocyanin" - CORRECT
P700 is the reaction center of Photosystem I (PSI). After electrons pass through cytochrome b6f complex, plastocyanin (a copper-containing protein) carries them to P700. This is a well-established step in the ETC.
Statement C: "NADPH is produced at the end of light reaction" - CORRECT
After PSI, electrons reduce NADP⁺ to NADPH via the enzyme NADP⁺ reductase. NADPH is one of the final products of the light reaction, used in the Calvin cycle.
Statement D: "The hydrogen ions produced during light reaction get concentrated in thylakoid lumen" - CORRECT
As electrons move through the ETC, protons (H⁺) are pumped from the stroma into the thylakoid lumen, creating a proton gradient. This proton concentration drives ATP synthesis via ATP synthase.
Correct combination: B, C, and D → Option 4
