The correct answer is option 1, Cytochrome oxidase. Copper is an important cofactor for many enzymes in the body, including cytochrome oxidase, which is a key enzyme involved in cellular respiration. Cytochrome oxidase is responsible for transferring electrons to oxygen during the final step of the electron transport chain in mitochondria, ultimately producing water and ATP. If copper is deficient, the activity of cytochrome oxidase can be significantly impaired, leading to decreased energy production and other cellular dysfunctions. This highlights the essential role of copper in mitochondrial function and overall cellular metabolism. The other options listed (option 2: Succinic dehydrogenase, option 3: Catalase, option 4: Acid phosphatase) are not directly associated with copper as a cofactor in mitochondrial enzymes.