Biologist: Researchers believe that dogs are the descendants of domesticated wolves that were bred to be better companions for humans. It has recently been found that some breeds of dog are much more closely related genetically to wolves than to most other breeds of dog. This shows that some dogs are descended from wolves that were domesticated much more recently than others. Which one of the following principles underlies the biologist's argument? ['If one breed of dog is more closely related to wolves than to another breed of dog, then the former breed of dog has more recent undomesticated wolf ancestors than the latter breed has.', 'Any breed of dog descended from wolves that were domesticated is more closely related genetically to at least some other breeds of dog than to wolves.', 'Any two breeds of dog that are more closely related to each other than to wolves are both descended from wolves that were domesticated long ago.', 'If one breed of dog is more closely related to wolves than another breed of dog is, then the former breed of dog is more closely related to wolves than to the latter breed of dog.']