Which of the following statements about oxidative phosphorylation is correct?

• A. It relies on a proton gradient across the inner mitochondrial membrane and uses oxygen as the final electron acceptor.
• B. It does not involve a proton gradient or oxygen.
• C. It occurs in the cytoplasm and does not require mitochondria.
• D. It is driven by substrate-level phosphorylation alone.

Answer: (A)