The relation which Skinner has with rats and Thorndike has with cats, same…

Concept: Several early-20th-century learning-theory researchers are each remembered for landmark experiments conducted on one particular animal species — the species pairs uniquely with the researcher and the school of thought their experiments established.

Application: Thorndike's puzzle-box experiments (trial-and-error learning, the Law of Effect) used cats, and Skinner's operant-conditioning experiments (the Skinner box) used rats. Wolfgang Köhler, a Gestalt psychologist, ran his own landmark experiments on chimpanzees — most famously a chimpanzee named Sultan, who solved problems such as reaching a banana placed out of reach by stacking boxes or joining sticks. Köhler argued the chimpanzee reached the solution through sudden insight — perceiving the relationships in the whole situation — rather than blind trial and error. This makes chimpanzees the animal that completes the analogy for Köhler, just as rats complete it for Skinner and cats for Thorndike.

Cross-check: Checking the remaining options against their actual researcher-animal pairings rules each out:

• Dogs pair with Ivan Pavlov's classical-conditioning (salivation-reflex) experiments, not with Köhler's.

• Monkeys pair with Harry Harlow's attachment experiments (the wire-versus-cloth surrogate-mother studies), not with Köhler's.

• Hens are not the signature subject of any major learning-theory experiment in this set.

So chimpanzees is the option that correctly completes the analogy.