Nicolas Has Autistic Disorder and Is Mute

Multiple Choice

Nicolas has autistic disorder and is mute. A therapist working with Nicolas initially gave him a piece of chocolate any time he made a sound with his lips. This slowly changed until Nicolas only received a piece of chocolate for saying complete words, and eventually only for saying complete sentences. In this example, Nicolas developed speech skills through the use of ​

A) classical conditioning.
B) modeling.
C) shaping.
D) negative reinforcement.