Answer: b. Neutral stimulus
Ivan Pavlov is known for his studies about classical conditioning where one can learn through establishing associations between different events and stimuli.
In his experiment about dogs, the bell represents neutral stimulus that is paired with food as unconditioned stimulus, which produce involuntary bodily response such as salivating.
Therefore, the bell as neutral stimulus before the experiment began can now trigger a response all on its own to that produced by the food. This means that an individual has learned that neutral stimulus is equals to something good just like the unconditioned stimulus.
