Purebred dogs are prone to genetically determined abnormalities. Although such abnormalities often can be corrected by surgery, the cost can reach several thousand dollars. Since nonpurebred dogs rarely suffer from genetically determined abnormalities, potential dog owners who want to reduce the risk of incurring costly medical bills for their pets would be well advised to choose nonpurebred dogs. Which one of the following if true, most seriously weakens the argument? ['All dogs, whether purebred or nonpurebred, are subject to the same common nongenetically determined diseases.', 'A dog that does not have genetically determined abnormalities may nevertheless have offspring with such abnormalities.', 'The purchase price of nonpurebred dogs tends to be lower than the purchase price of purebred dogs.', "Most genetically determined abnormalities in dogs do not seriously affect a dog's general well-being."]