Alika is allergic to grass. whenever he would sit on the grass, his skin would break out in hives that made him feel very itchy. now, if you just say the word "grass" to him, he starts to feel itchy. in this example, the word "grass" is:

In this instance, the word grass is a conditioned stimulus. 

A conditioned stimulus (CS) is a neutral stimulus, that when repeatedly followed by an unconditioned stimulus (UCS), elicits the same response as the UCS. In this example, the CS is the word, "grass", because the word, "grass" alone elicits a response of itchiness in Alika without the presence of actual grass. 

Where are the choices?