Because the question does not ask about the effects on the dog, we can deduce that the tones were stimuli. Given that these stimuli elicited no response from the dogs, they can be initially labeled as neutral stimuli because there is no learned association with food at this time. 

In Pavlov's experiment, he coupled what was once a neutral stimulus with an association (food) for the dogs. This neutral stimulus became associated with food through a learned process, thus becoming a conditioned stimulus for what was once an unconditioned response. 

Given that the problem is referring to the effect on the dog, salivation can be labeled as a response. Because it is a tone that's creating the salivation and not the food itself, it observes an association that was learned. Therefore, the dog was conditioned to expect food upon hearing the bell. Salivation, in this situation, is a conditioned response. 

Because the smell of food is eliciting Max's hunger, it is a stimulus. Given that the stimulus is being experienced prior to his conditioning at school, the smell of the food during summer acts as the unconditioned stimulus. 

The announcement would ideally initially act as a neutral stimulus because Max has learned to associate the smell of food with the ringing of the lunch bell. Given that the announcement does not sound anything like the lunch bell, Max will not experience that association and therefore not feel that immediate hunger. 

It was the odor of the food that made Max hungry. Much like Pavlov's dogs, where the sight of food was enough to always make them salivate. This parallels Pavlov's work in that the smell of food is the unconditioned stimulus, and therefore the hunger the unconditioned response. In this case, the school bell acts synonymously to Pavlov's tones in that it was learned to be associated with food. Max learns to associate the lunch bell with the smell of food, which in turn makes him hungry. Therefore it is the conditioned stimulus. 

Extinction is when the conditioned response (salivating at the sound of a bell) stops because the conditioned stimulus (bell) is no longer presented together with the unconditioned stimulus (steak). 

As for the other answers, acquisition is the learning of a conditioned response and is the period when the US and CS are presented together. Generalization is when the conditioned response occurs with a similar but slightly different conditioned stimulus. Spontaneous recovery is the reappearance of the conditioned response after extinction when the US and CS are paired together again. Discrimination is the opposite of generalization (distinguishing between a CS different from the original CS).

Three types of conditioning that are good to know are delayed conditioning, trace conditioning, and simultaneous conditioning. Delayed conditioning is presenting the US while the CS is still active, trace conditioning is presenting the CS then a short break and then presenting the US, and simultaneous conditioning is presenting the CS and the US at the same time. Delayed conditioning is considered to be the most effective (acquisition occurs the fastest) because of its timing; trace conditioning allows for too much time between the US and the CS for the pairing to be strong, while simultaneous conditioning is too much stimulation at the same time for the pairing to be ingrained. 

Concurrent conditioning and break conditioning do not actually exist-- they were distracting answers. 

During the famous Little Albert study, the boy was conditioned to fear a white rat because its presentation was paired with an unpleasant noise.

This study revealed that humans can be classically conditioned in addition to animals, aversive conditioning (conditioning of negative reactions) is possible, fear can be conditioned, and complex reactions can be conditioned. Since the main takeaway from Little Albert is that humans can be effectively classically conditioned, the answer choice "classical conditioning is much more effective on less complex animals (like rats) than it is on humans" misses the mark.

Acquisition is a process in classical conditioning. By definition, it is considered the first stage of classical conditioning where an individual links a neutral stimulus to an unconditioned stimulus. For instance, during Pavlov's experiment, this was when the dogs made a connection between the tone and the sight of food. In turn, the neutral stimulus will begin to initiate the conditioned response (in Pavlov's experiment, that meant salivation).