Your Friend's Mother Was Always Baking Ginger-Flavoured Cookies Whenever You

Your friend's mother was always baking ginger-flavoured cookies whenever you were at her house.You loved those cookies,and would eat several each time you visited.One day,you noticed that you started to salivate as soon as you walked up the front steps to the house,before you even smelled the cookies.The reason for this is that the house has become a(n) :

A) unconditioned response.
B) unconditioned stimulus.
C) conditioned response.
D) conditioned stimulus.