In Pavlov's original experiments, dogs were classically conditioned to respond to the ticking of a metronome with salivation. According to Robert Rescorla and the cognitive perspective, the dogs learned: a. that the bell was a signal that reliably predicted that food would follow. b. that salivating at the sound of a bell would be reinforced by food. c. helplessness because of being restrained by a harness. d. a reflexive association between a ringing bell and food.