Some Present-Day Bacteria Use a System of Anaerobic Respiration Characterized

Some present-day bacteria use a system of anaerobic respiration characterized by an electron transport chain analogous to that found in aerobic organisms. Which of the following correctly characterizes the anaerobic electron transport chain?

A) It uses oxygen as a final electron acceptor.
B) It is embedded in the outer mitochondrial membrane rather than the inner mitochondrial membrane.
C) It establishes a proton gradient between the cytoplasm and the extracellular fluid.
D) It establishes a proton gradient between the intermembrane space and the cytoplasm.
E) None of these answer options accurately characterizes the anaerobic electron transport chain.