The Current Theory Is That Chloroplasts Are Descendants of Symbiotic

The current theory is that chloroplasts are descendants of symbiotic cyanobacteria that lived within eukaryotic cells. If we look at their respective genomes, however, we see that the cyanobacteria have many more genes than do chloroplasts. Where did these genes go?

A) Restriction enzymes removed them.
B) Endosymbiosis requires a reduction in genetic material in order to be successful.
C) Many of the genes were transported to the nucleus, and others were lost.
D) Nowhere; cyanobacteria and chloroplasts actually have the same number of genes.
E) None of the answer options is correct.