When hydrogen ions are pumped out of the mitochondrial matrix, across the inner mitochondrial membrane, and into the space between the inner and outer membranes, the result is damage to the mitochondrion:______.

A. damage to the mitochondrion.

B. the reduction of NAD.

C. the restoration of the Na-K balance across the membrane.

D. the creation of a proton gradient.

E. the lowering of pH in the mitochondrial matrix.