What Can You Conclude by the Observation That Chloroplasts Are

What can you conclude by the observation that chloroplasts are monophyletic?

A) The same cyanobacteria were engulfed by multiple hosts that were ancestral to the red and green algae.
B) Aerobic bacteria were engulfed by eukaryotic cells forming plant cells.
C) Cyanobacteria were engulfed by all eukaryotic cells.
D) Cyanobacteria reproduced by sexual reproduction once engulfed by brown algae leading to the formation of protists.