All are responsible for establishment of proton gradient across the thylakoid membrane except:

Causes for the development of proton gradient across the thylakoid membrane:(a) splitting of the water molecule takes place on the inner side of the membrane, the protons or hydrogen ions that are produced by the splitting of water accumulate within the lumen of the thylakoids.(b) During electron transport from plastoquinone to cyt b6f 2 H+ from the stroma is released into the lumen of the thylakoid.(c) The NADP reductase enzyme is located on the stromal side of the membrane. Along with electrons that come from the acceptor of electrons of PS I, protons are necessary for the reduction of NADP+ to NADPH+ H+. These protons are also removed from the stroma.