In oxidative phosphorylation, which of the following links the respiratory chain and ATP production?

Mitchell's chemiosmotic theory postulates that the energy from oxidation of components in the respiratory chain is coupled to the translocation of hydrogen ions (protons, H+) from the inside to the outside of the inner mitochondrial membrane. The electrochemical potential difference resulting from the asymmetric distribution of the hydrogen ions is used to drive the mechanism responsible for the formation of ATP. Ref: Harper's Illustrated Biochemistry, 26th Edition, Pages 95-96; Textbook of Biochemistry By D M Vasudevan, 3rd Edition, Pages 210-11