During strenuous exercise, the NADH formed in the glyceraldehyde 3-phosphate dehydrogenase reaction in skeletal muscle must be reoxidized to NAD+ if glycolysis is to continue. The most important reaction involved in the reoxidation of NADH is:
A) dihydroxyacetone phosphate glycerol 3-phosphate
B) glucose 6-phosphate fructose 6-phosphate
C) isocitrate a-ketoglutarate
D) oxaloacetate malate
E) pyruvate to lactate.