Answer:
2. Conditioned stimulus
Step-by-step explanation:
Conditioned stimulus -
It refers to as the neutral stimulus , which triggers or initiates the conditioned response , is referred to as the conditioned stimulus .
Ivan Pavlov was the very first one to give meaning to the term conditioned stimulus , by experimenting on the dogs .
Hence , from the given scenario of the question ,
The correct answer is 2. conditioned stimulus .