Although many chimpanzees live in environments containing oil palm nuts, members of only a few populations use stones to crack open the nuts. The likely explanation is that A) the behavioral difference is caused by genetic differences between populations. B) members of different populations have different nutritional requirements. C) the cultural tradition of using stones to crack nuts has arisen in only some populations. D) members of different populations differ in learning ability. E) members of different populations differ in manual dexterity.