The Earliest Fossil Records of Bacteria-Like Organisms,dated at Over 3

The earliest fossil records of bacteria-like organisms,dated at over 3 billion years,________.

A) are too spotty to allow us to trace lines of descent to present-day organisms
B) unquestionably belong to cyanobacteria
C) show that early cells had membranes made of short amino acid chains
D) used only RNA molecules for both information storage and chemical catalysis
E) already contained endosymbiotic organelles