Carlos Is Afraid of Snakes

Carlos is afraid of snakes. To help Carlos overcome his fear, his therapist first shows him pictures of snakes and then gives him a toy snake to handle. Eventually, she and Carlos visit the reptile house at the zoo where Carlos can observe snakes at a distance in their glass enclosures. Finally, the therapist asks a friend who keeps pet snakes to bring some of the smaller, nonpoisonous snakes in so Carlos can pet them. The method Carlos' therapist is using to help him overcome his fear is an example of:

A) rechaining events.
B) fatiguing the response.
C) systematic desensitization.
D) interfering with S-R associations.