Explanation
The correct answer is C: Cytochrome c Oxidase Complex.
The electron transport chain (ETC) is a series of protein complexes and electron carrier molecules located in the inner mitochondrial membrane that transfer electrons from electron donors to electron acceptors via redox reactions. The final protein complex in the electron transport chain is Complex IV or Cytochrome c Oxidase Complex, which is responsible for transferring electrons from cytochrome c to oxygen, ultimately reducing it to water.