Among people who live to the age of 100 or more, a large proportion have led "unhealthy" lives: smoking, consuming alcohol, eating fatty foods, and getting little exercise. Since such behavior often leads to shortened life spans, it is likely that exceptionally long-lived people are genetically disposed to having long lives. Which one of the following, if true, most strengthens the argument? ['Nearly all people who live to 100 or more have siblings who are also long-lived.', 'Some of the exceptionally long-lived people who exercise regularly and avoid fatty foods do smoke or consume alcohol.', 'Some people who do not live to the age of 100 also lead unhealthy lives.', 'Some of the exceptionally long-lived people who do not smoke or drink do eat fatty foods and get little exercise.']