Your friend's mother was always baking ginger-flavored cookies whenever you were at their house. you loved those cookies, and would eat several each time you visited. one day, you noticed that you started to salivate as you walked up the front steps to the house, before you smelled the cookies. the reason for this is that the house has become a(n):
a) unconditioned stimulus
b) conditioned response
c) unconditioned response
d) conditioned stimulus