As Susie left for work, she said “goodbye” to her husband and slammed the door. The loud sound of the door made her husband flinch. After many mornings of hearing “goodbye” followed by a door slam, her husband flinches when he hears her say, “goodbye.” In this scenario, hearing the word “goodbye” is the

The husband had to be conditioned to react negatively to the word "goodbye". Therefore, the stimulus is conditioned.