When Comparing Different Viral Species, Some Genes Can Be Clearly

When comparing different viral species, some genes can be clearly identified as being related due to their sequence similarity, which indicates a common lineage between two species. However, in some instances other genes can also be found that are completely unrelated and thus contradict evidence of shared ancestry. Such observations could be explained by

A) viral conjugation.
B) inactive polymerase error checking mechanisms.
C) different host specificities between viral species.
D) recombination events occurring within viruses across the species barrier.
E) All options listed here are correct.