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 ⇌ α-ketoglutarate.
d) oxaloacetate ⇌ malate.
e) pyruvate ⇌ lactate.