Answer:
C
Explanation:
All organisms including anaerobic organisms undergo respiration. The difference in the cellular respiration of aerobes and anaerobes is that oxygen is the final electron acceptor in aerobic cellular respiration while another element is the electron acceptor in anaerobic respiration.
This process of transferring electrons in cellular respiration occurs during the electron transport chain (ETC). According to the question, the anaerobic organism converts Fe3 to Fe2 during respiration, meaning that iron is its final electron acceptor during ETC.
In chemistry, an electron acceptor accepts an electron (e-) and become reduced itself. In this case, the oxidation state of iron reduced from +3 to +2 because it accepted one electron (e-).