molly automatically feels happy every time she has pizza for dinner. molly’s mom always gets her pizza from the pizza shoppe. at first, pulling into the pizza shoppe parking lot does not affect the way molly feels. but after a while, molly starts to feel happy just when the car turns into the pizza shoppe lot because she knows it means they will have pizza for dinner. in this example, the pizza shoppe parking lot is the

Conditioned stimulus.

Explanation:

The conditioned stimulus is a previously neutral stimulus that, after becoming associated with the unconditioned stimulus will overtime trigger a conditioned response.

That means, what before was neutral (pulling into The Pizza Shoppe parking lot) will eventually be associated with the unconditioned stimulus (in this case is Molly feeling happy when she has pizza, what is a natural response) and becomes a conditioned stimulus making Molly happy for anticipation.  

So, in this example, The Pizza Shoppe parking lot is the conditioned stimulus.