The oxidation of which of the following will produce FADH₂?

Explanation

The correct answer is succinate. In the citric acid cycle, succinate is oxidized to fumarate by the enzyme succinate dehydrogenase. During this reaction, FAD is reduced to FADH₂, which is essential for the electron transport chain and ATP production. Malate is involved in a different step, converting to oxaloacetate and producing NADH instead. Fumarate is a product of succinate oxidation and does not directly produce FADH₂.. FAD is a coenzyme, not a substrate, and is reduced during succinate oxidation, not oxidized itself.