A Laboratory Analysis of Isolated Mitochondria Demonstrates That Oxygen Consumption

A laboratory analysis of isolated mitochondria demonstrates that oxygen consumption is normal when succinate is added but extremely low when pyruvate and malate are used. The mitchondria are subsequently shown to have normal cytochromes but a reduced iron content. The reduced pyruvate/malate oxidation is due to a defect in which of the following respiratory components?

A) cytochrome c
B) cytochrome oxidase
C) NADH dehydrogenase
D) succinate dehydrogenase
E) ubiquinone