Answer:
B) positive reinforcers for staying close
Step-by-step explanation:
In psychology and operant conditioning, we learned based on reinforcements and punishments.
A reinforcement refers to an stimulus that makes the desired behavior more likely to appear, while punishment refers to an stimulus that makes the behavior less likely to appear.
When we talk about a positive reinforcement, we are talking about giving the subject something desirable in order to make the desired behavior more likely to appear.
In this example, Lydia would pet her new dog and give him treats for staying close during walks. Now, the dog stays by her side even when he is not on a leash. We can see that Lydia gave the dog something desirable (pets and treats) and this made the behavior of staying close to be learned by him. Thus, petting and receiving treats acted as positive reinforcers for staying close.