The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is

A)oxidation of glucose to CO₂ and water.
B)the thermodynamically favourable flow of electrons from NADH to the mitochondrial electron transport carriers.
C)the final transfer of electrons to oxygen.
D)the proton-motive force across the inner mitochondrial membrane.
E)the thermodynamically favourable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.