Answer:
C. Unconditioned Response (UR)
Explanation:
The stimulus is something that happens to you or that is said to you that provoques a respones in your organism, as the last time he saw the pictures of the lake property he was mouth-watering, when he saw them again, the response was to salivate again, but it is a unconditioned response, unless the real estate agent actually wanted it to be the case, if he continued to show him pictures of houses while he was eating, then that is a conditioned response, but as this seems more like a random situation, it is an unconditioned response.
