What Implication Does the Composition of Cometary Nuclei Have for the Creation

What implication does the composition of cometary nuclei have for the creation of life?

A) They are made entirely of liquid water, which is needed by all life.
B) They hold organic compounds, evidence that the ingredients necessary for the creation of life were present in the early solar nebula.
C) Bacteria have been found in cometary nuclei, proving that life on Earth came from comets.
D) They hold oxygen, which is needed for all life.
E) Cometary impacts would have been "softer" than asteroid impacts, helping to prevent mass extinctions.