## **Core Concept**
The question tests knowledge of enzymes that contain copper as a cofactor, which is crucial for their catalytic activity. Copper plays a significant role in various enzymatic reactions, particularly those involved in oxidation-reduction processes.

## **Why the Correct Answer is Right**
The correct answer, **Cytochrome c oxidase**, is a key enzyme in the mitochondrial electron transport chain. It catalyzes the transfer of electrons from cytochrome c to oxygen, the final electron acceptor, resulting in the formation of water. This process is essential for generating ATP during oxidative phosphorylation. Cytochrome c oxidase contains copper ions, which are vital for its function, as they participate directly in the electron transfer process and the reduction of oxygen.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While certain enzymes are involved in antioxidant defenses, the specific reference to a copper-containing enzyme points more directly to an enzyme like cytochrome c oxidase rather than a general antioxidant enzyme.
- **Option B:** This option is not specified, but if it refers to another enzyme, it would be incorrect because it does not contain copper as a cofactor.
- **Option D:** Similarly, this option is unspecified but would be incorrect if it refers to an enzyme not known to contain copper.

## **Clinical Pearl / High-Yield Fact**
A memorable point for exams is that **Wilson's disease**, a genetic disorder characterized by excessive accumulation of copper in the body, leads to liver disease, neurological symptoms, and psychiatric problems. This condition highlights the importance of copper homeostasis and its role in enzyme function.

## **Correct Answer:** . **Cytochrome c oxidase**