During light reaction as electrons move through photosystems, protons are transported across the membrane. This happens because

The primary acceptor of e– transfers only its e^- to carrier

The primary acceptor of e– transfers only its H⁺ to the nearest  carrier

NADP reductase is present in grana

The primary acceptor of electron (located towards the outer surfaces of the membrane) transfers its electron not to an electron carrier but to H⁺ carrier