Evidence That Animals Learn to Expect a Certain Type of Reinforcer

Multiple Choice

Evidence that animals learn to expect a certain type of reinforcer in an operant conditioning situation comes from studies that

A) trained two responses with two different reinforcers,then associated one of the two reinforcers with poison
B) trained two responses with two different reinforcers,then satiated the animals with one of the reinforcers
C) changed the type of reinforcer and found that animals looked "surprised"
D) all of the above