Scenario The First Prokaryotic Cells Gave Rise to Eukaryotic Cells Approximately

Scenario
The first prokaryotic cells gave rise to eukaryotic cells approximately 1.7 billion years ago. The structure of eukaryotic cells today suggests how they might have evolved from their prokaryotic ancestors. Scientists examining mitochondria and chloroplasts now think that these organelles were probably free-living prokaryotes before becoming a part of eukaryotic cells long ago.
-Which characteristic of chloroplasts suggests that they might have evolved from free-living bacteria?

A) Chloroplasts have cell walls.
B) Chloroplasts contain pigments.
C) Chloroplasts have their own DNA.
D) A single, highly folded plasma membrane surrounds chloroplasts.