13. 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 lactate.