The correct option is D All of the above
Chemiosmosis is defined as the movement of ions across a semipermeable membrane, down their electrochemical gradient.
A good example of this process is the generation of adenosine triphosphate (ATP) by the movement of hydrogen ions across a membrane during photosynthesis.
During photosythesis, a proton pump, ATP synthase, allows protons to move along a proton gradient across a membrane and inturn phosphorylate adenosine diphosphate (ADP), making ATP.