Long-Term Studies of Belding's Ground Squirrels Show That Immigrants Move

Long-term studies of Belding's ground squirrels show that immigrants move nearly 2 km from where they are born and become 1%-8% of the males and 0.7%-6% of the females in other populations. On an evolutionary scale, why is this significant?

A) These immigrants make up for the deaths of individuals, keeping the other populations' size stable.
B) Young reproductive males tend to stay in their home population and are not driven out by other territorial males.
C) These immigrants provide a source of genetic diversity for the other populations.
D) Those individuals that emigrate to these new populations are looking for less crowded conditions with more resources.
E) Gradually, the populations of ground squirrels will move from a clumped to a uniform population pattern of dispersion.