An anxiety hierarchy is: a. a computer program that generates random images of scenes that virtually everyone finds terrifying. b. a description of all the symptoms a person experiences during an episode of intense anxiety. c. a list of specific anxiety-producing scenes, arranged from least to most anxiety-provoking, that are related to the person's fear or phobia. d. a complete list of all of the objects or situations that have ever produced anxiety in the person, arranged in order of intensity.