'A Conditioned stimulus' is elucidated as the stimulus that was previously neutral eventually leads to evoke a learned response with training. Such a stimulus is contradictory to unconditioned or naturally occurring stimulus which triggers a specific response naturally while the former elicits a response through learning from the various factors.
As per the question, the 'opening of refrigerator' exemplifies a 'conditioned stimulus' as it evokes a learned response from the 'dog' as it runs to the kitchen every time 'refrigerator is opened'. Therefore, 'it demonstrates a conditioned stimulus' as Jasmine learns with time that 'every time the door is opened, he gets some food'.
