Frank Is Working with Garrett to Increase His Ability to Keep

Frank is working with Garrett to increase his ability to keep track of his class materials. Garrett is constantly leaving his books and papers behind in class, in his locker, or at home. Frank observes and tracks Garrett's behavior for four days. To determine how often he actually does leave his materials behind. He then introduces a required assignment book strategy. In each class Garrett must write down what he needs to do and the materials that the task will require. Frank continues to observe Garrett's behavior. However, under the assignment book strategy, Garrett's behavior doesn't change. Frank decides that he will also require that Garrett get signatures from his teachers and parents in his assignment book. After four weeks, Frank removes the required assignment book and signature and observes and records Garrett's behavior for a week.
-In Frank's study, the signed assignment book represents which of the following?

A) A
B) B
C) S
D) T