Final answer:
Jennifer is using systematic desensitization to practice and relax to each item on a hierarchy related to a situation she finds frightening.
Step-by-step explanation:
Jennifer is using systematic desensitization.
Systematic desensitization is a technique used to treat phobias or fears by gradually exposing the person to the feared object or situation in a relaxed state. This technique helps the individual develop a new response to the feared stimulus by learning to associate it with relaxation instead of fear. In Jennifer's case, she is practicing relaxation to each item on a hierarchy related to a situation she finds frightening, which is a key component of systematic desensitization.