Statement A: Malonic acid is competitive inhibitor for the activity of succinic dehydrogenase.
Statement B: Malonic acid structurally resembles succinic dehydrogenase.
Malonic acid is competitive inhibitor of succinate dehydrogenase and it structurally resembles succinic acid but not succinic dehydrogenase. It can occupy the active site of the enzyme and inhibit the conversion of succinate to fumarate.