The Following Questions Refer to the Information Below -What Probably Explains the Inclusion of Rabbits in This Research

The following questions refer to the information below.
A researcher compared the nucleotide sequences of a homologous gene from five different species of mammals with the homologous human gene. The sequence homology between each species' version of the gene and the human gene is presented as a percentage of similarity.
$$\begin{array} { l c } \text { Species } & \text { Percentage } \\\hline \text { Chimpanzee } & 99.7 \\\text { Orangutan } & 98.6 \\\text { Baboon } & 97.2 \\\text { Rhesus Monkey } & 96.9 \\\text { Rabbit } & 93.7\end{array}$$

-What probably explains the inclusion of rabbits in this research?

A) Their short generation time provides a ready source of DNA.
B) They possess all of the shared derived characters as do the other species listed.
C) They are the closest known relatives of rhesus monkeys.
D) They are the outgroup.
E) They are the most recent common ancestor of the primates.