Wolves that were tempted into eating sheep carcasses laced with poison develop an aversion to sheep meat. Which of the following provided the initial evidence leading to this practice?

A: John Garcia's studies on the importance of biological predispositions in conditioning
B: Martin Seligman's research on learned helplessness
C: Edward L. Thorndike's research the law of effect
D: B.F. Skinner's studies on intermittent schedules of reinforcement
E: Robert Rescorla's research on the importance of cognition in classical conditioning