Why Is It the Case That If You Identify Yourself

Why is it the case that if you identify yourself as African American,it is possible that you are genetically more similar to a randomly chosen person who is White,Hispanic,or Asian than you are to another African American who is not a direct blood relative?

A) The human populations in other parts of the world have been physically separated from each other longer than have many human populations in Africa.
B) The genes of African Americans tend to mirror-become more similar to--the genes of other people with whom they come into contact to a greater extent than do the genes of Whites,Hispanics,or Asians.
C) Many human populations in Africa have been physically separated from each other longer than they have been separated from the human populations in other parts of the world.
D) The genes of Whites,Hispanics and Asians tend to mirror-become more similar to-the genes of other people with whom they come into contact to a greater extent than do the genes of African Americans.