Final answer:
In classical conditioning, the conditioned stimulus (CS) signals the impending occurrence of the unconditioned stimulus (US). The formula container becoming a trigger for a baby's excitement and salivation before receiving food is an example where the container is the CS, the food the UCS, and the baby's excited behavior represents the CR.
Step-by-step explanation:
Classical Conditioning Components:
In classical conditioning, the conditioned stimulus (CS) signals the impending occurrence of the unconditioned stimulus (US). The correct option is therefore C) CS; US. In the example where a tone is paired with meat powder to elicit salivation in dogs, the tone becomes the CS, which predicts the arrival of the meat powder, the US. Initially, the dogs salivate in an unconditioned response (UCR) to the meat powder (UCS). After conditioning, the sound of the tone alone, now the CS, will cause the dogs to salivate, which is the conditioned response (CR).
Example of Classical Conditioning in Humans:
Similarly, when a baby like Angelina gets excited and reaches for food upon seeing a formula container, that container has become the CS that predicts the UCS (the actual formula), leading to the UCR and CR of excitement and possible salivation. The neutral stimulus has been transformed into a CS through repeated pairings with the UCS.