The Cell Harvests a Very Large Amount of Free Energy

The cell harvests a very large amount of free energy from glucose in the form of ATP.Which statement can be used as part of an explanation about how the cell accomplishes this harvesting process with high efficiency (i.e., with very little loss in energy as heat) ?

A) Electron transport uses a series of several proteins, each of which functions to capture a portion of the total energy of the electrons entering the chain.
B) The net energy change for the transfer of electrons from NADH to oxygen is very large.
C) Pyruvate oxidation and the citric acid cycle cannot operate unless oxygen is available to function as the final acceptor of electrons.
D) Electron flow through the respiratory chain results in the active transport of protons across the inner mitochondrial membrane, creating a proton concentration gradient.
E) NADH and FADH₂ enter the electron transport chain at different points.