Which Catabolic Processes May Have Been Used by Cells on Ancient

Multiple Choice

Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available?

A) only glycolysis and fermentation
B) only glycolysis and the citric acid cycle
C) only glycolysis and pyruvate oxidation
D) only oxidative phosphorylation,using an electron acceptor other than oxygen
E) glycolysis,pyruvate oxidation,the citric acid cycle,and oxidative phosphorylation,using an electron acceptor other than oxygen