Donna is about 25 pounds overweight, has tried a variety of diets, and has repeatedly failed to maintain weight loss. She defends her weight with the explanation that almost all of her relatives are overweight, and none has ever been successful with attempts to lose weight. Donna can best be described as: a. having an internal locus of control. b. having an external locus of control. c. being a victim of genetics. d. being unmotivated.