The Study of Comparative Genomics Has Given Researchers the Ability

The study of comparative genomics has given researchers the ability to look at multiple genomes from different species,which has led to new ideas about the evolutionary history of organisms.The conclusion is that

A) modern vertebrate species all evolved from very different ancestral species,so there is little similarity between their genomes.
B) modern vertebrate species all evolved from the same ancestral species,but they have changes so that their genomes are very different in modern times.
C) ancestral species contained very similar genomes,but modern vertebrate species have significant differences in their genomes.
D) modern vertebrate species evolved from the same ancestors and a large portion of their genome is conserved.
E) neither the ancestral species nor the modern one resemble each other genetically.