Refer to Figure 9

Refer to Figure 9.2, showing the citric acid cycle, as a guide to answer the following questions.

-The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is

A) oxidation of glucose to CO² and water.
B) the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers.
C) the final transfer of electrons to oxygen.
D) the difference in H⁺ concentrations on opposite sides of the inner mitochondrial membrane.
E) the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.