The First Cells Were Most Likely Heterotrophic Anaerobes Because

The first cells were most likely heterotrophic anaerobes because:

A) they were dependent upon cyanobacteria for oxygen.
B) they manufactured organic molecules and needed oxygen.
C) they manufactured organic molecules and do not need oxygen.
D) they utilized preformed organic molecules and needed oxygen.
E) they utilized preformed organic molecules and did not need oxygen.