Researchers have found that mitochondria and chloroplasts in eukaryotic cells have their own DNA. This DNA is different from the DNA in a eukaryotic cell's nucleus. Chloroplasts and mitochondria use their own DNA and ribosomes to make some organelle-specific proteins.

What statement is best supported by this information?

A.
Modern cells could exist without mitochondria and chloroplasts.

B.
Early eukaryotic cells engulfed prokaryotic cells, which later became mitochondria and chloroplasts.

C.
Early prokaryotic cells engulfed eukaryotic cells, which later became mitochondria and chloroplasts.

D.
Mitochondria and chloroplasts could exist outside of modern cells.