Which statement correctly contrasts substrate-level phosphorylation and oxidative phosphorylation?

Which statement correctly contrasts substrate-level phosphorylation and oxidative phosphorylation?

• A. Substrate-level phosphorylation uses a proton gradient; oxidative phosphorylation transfers phosphate from substrate to ADP.
• B. Substrate-level phosphorylation transfers a phosphate from a substrate to ADP; oxidative phosphorylation uses a proton gradient to drive ATP synthase and occurs on the inner mitochondrial membrane.
• C. Substrate-level occurs in mitochondria only; oxidative phosphorylation occurs in the cytosol.
• D. Substrate-level phosphorylation only occurs during fermentation; oxidative phosphorylation occurs in the mitochondria.

Answer: (B)