Chloroplasts and mitochondria are thought to be of prokaryotic origin. One piece of evidence that supports this hypothesis is that these organelles contain prokaryotic-like ribosomes. These ribosomes are probably most similar to ribosomes found __________.

• A. free in the cytoplasm of eukaryotes
• B. on the rough ER
• C. free in the cytoplasm of eukaryotes and on the rough ER
• D. free in the cytoplasm of eukaryotes, on the rough ER, and in bacterial cells
• E. in bacterial cells