Which of the following best describes diversity in terms of natural selection

Which of the following best describes diversity in terms of natural selection.  (A) Most populations of organisms evolve to become more and more alike, eventually becoming genetic clones. (B) Some individuals in a population have a variation that gives them an advantage to survive and reproduce. (C) If a population becomes isolated from others, the possibility for mutations to occur decreases and extinction results. (D) A stable environment and less variations in a population's gene pool promotes evolution of a new species.
The answer is B. Some individuals in a population have a variation that gives them an advantage to survive and reproduce.