Dr Jackson Is Creating a Study to Evaluate the Usefulness

Dr. Jackson is creating a study to evaluate the usefulness of a new therapy treatment for borderline personality disorder. She personally trains all of the therapists who will be used in her study and creates a detailed treatment manual that gives specific instructions regarding how all therapists are supposed to address various issues. What should be the next phase of her study?

A) Preparation phase
B) Treatment phase
C) Participant screening phase
D) Assessment phase