When Julie's Father Comes Home from Work He Opens the Front

Multiple Choice

When Julie's father comes home from work he opens the front door and picks her up to give her a big hug. Before long, Julie starts smiling whenever she hears her father turn his key to open the door. In this situation, Julie's smiling at the sound of her father's key turning in the door is an) _____; the hugging is an) _____.

A) unconditioned stimulus; conditioned response
B) unconditioned response; conditioned stimulus
C) conditioned stimulus; unconditional response
D) conditioned response; unconditional stimulus