Final answer:
Sulfate-reducing bacteria and archaea use sulfate as a final electron acceptor in anaerobic respiration, replacing oxygen in the process.
Step-by-step explanation:
Sulfate-reducing bacteria and archaea use sulfate as a final electron acceptor in anaerobic respiration. They convert sulfate back to hydrogen sulfide, which takes the place of oxygen in their respiration process. Therefore, the correct answer is c) Sulfate.