**Core Concept**
Cytochrome oxidase, also known as Complex IV, is a crucial enzyme in the electron transport chain of mitochondria. It plays a vital role in the process of oxidative phosphorylation, where it helps to pump protons across the mitochondrial inner membrane, generating a proton gradient that drives ATP synthesis.

**Why the Correct Answer is Right**
Cytochrome oxidase contains heme a and copper ions as essential cofactors. Heme a is a porphyrin ring complexed with iron, which is involved in the binding and transfer of electrons. Copper ions, specifically CuA and CuB, are also integral to the enzyme's function, facilitating the transfer of electrons from cytochrome c to oxygen. This process ultimately leads to the production of water and the generation of a proton gradient.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately describe the cofactors present in cytochrome oxidase.
**Option B:** This option is incorrect as it refers to a different component of the electron transport chain, specifically Complex I.
**Option C:** This option is incorrect as it is not a known cofactor of cytochrome oxidase.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that cytochrome oxidase is a critical enzyme in the electron transport chain, and defects in its function can lead to mitochondrial disorders, such as Leigh syndrome. This condition is characterized by progressive neurological deterioration and can be caused by mutations in the genes encoding cytochrome oxidase subunits.

**Correct Answer: C. Heme a and copper ions.