Which of the Following Is the Best Example of 'Genetic

Which of the following is the best example of 'genetic adaptation'?

A) If a person who is not naturally strong works hard to build up a fit muscular physique, his or her children will be born strong and fit.
B) A giraffe that is born with a long neck will eat better and therefore survive better than a giraffe with a short neck, and then reproduce more giraffes with long necks, who in turn will be more likely to survive to produce offspring.
C) A giraffe that stretches its neck by reaching upwards to eat will have babies with longer necks than babies born to giraffes who do not stretch their necks.
D) A blacksmith who develops his or her arm muscles through hard work at the forge may have children who end up with strong arms, too, if they take on blacksmithing.
E) Runners from Kenya and Jamaica are born with a genetic advantage that makes them more likely to win in Olympic track and field events