Origins of mitochondria and chloroplasts

The origins of mitochondria and chloroplasts is thought to have involved Select one: O a. the uptake of free DNA from the environment. O b. the fusion of two archean cells to form an early eukaryote. Ос. prokaryotic cells that became internal symbionts within another prokaryotic/proto-eukaryotic cell. O d. prokaryotic cells being engulfed and becoming external symbionts within an early bacteria cell. Oе. the absorption of RNA from prokaryotic cells.