Final answer:
The therapist Frank is seeing is most likely using exposure therapy, which involves gradual exposure to fears in a controlled environment.
Step-by-step explanation:
The therapist Frank is seeing is most likely using exposure therapy. In exposure therapy, the individual is gradually exposed to the feared object or situation in a controlled and safe environment, allowing them to confront their fears and develop coping mechanisms to manage their anxiety. The development of a stimulus hierarchy is a key component of exposure therapy, as it involves creating a list of feared stimuli and arranging them in order of least to most anxiety-inducing, guiding the individual through gradual exposure to each level.