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 mitochondria suggests they might have evolved from free-living bacteria?

A) Mitochondria have cell walls.
B) The plasma membrane of a mitochondrion is the site of many important steps of cellular respiration.
C) Mitochondria have their own DNA.
D) Mitochondria rely upon proteins as their source of energy.