Answer:
The correct answer is A.
Step-by-step explanation:
Though animals may (or probably) be all linked by one source, organisms still have their own types of sequences in their DNA. Because of this, these form different species/organisms in the environment and create variety. For example if the DNA of a Red bird and a blue bird bred, it is possibly that they could create a newer variety of birds that could be a mixed species, having their own type of DNA, that is altered from the red and blue bird(s).
Hope this helped! :D