A Pigeon Can Easily Be Taught to Flap Its Wings

A pigeon can easily be taught to flap its wings in order to avoid shock but not for food reinforcement. According to the text,this is most likely so because

A) pigeons are biologically predisposed to flap their wings in order to escape aversive events and to use their beaks to obtain food.
B) shock is a more motivating stimulus for birds than food is.
C) hungry animals have difficulty delaying their eating long enough to learn any new skill.
D) of all of these reasons.