Aidan's therapist believes that cognitive-behavioral therapy will help to relieve the symptoms of his major depressive disorder. As part of this therapy, his therapist will most likely suggest that Aidan a. take an antidepressant for 8 weeks before coming back for another visit b. sit under a high-intensity light source for a short period each day c. expose himself to situations that make him feel depressed until his mood improves d. keep a journal to track his negative thoughts and then work to change his thoughts

Let's briefly analyze the options provided: a. Taking an antidepressant for 8 weeks before coming back for another visit - This option relates to medication, which is not part of cognitive-behavioral therapy. b. Sitting under a high-intensity light source for a short period each day - This is a treatment option for seasonal affective disorder, not specifically cognitive-behavioral therapy. c. Exposing himself to situations that make him feel depressed until his mood improves - This is a counterintuitive response and could potentially cause further harm to the individual. It is not aligned with cognitive-behavioral therapy. d. Keeping a journal to track his negative thoughts and then working to change his thoughts - This option is directly related to cognitive-behavioral therapy as it works on changing an individual's thoughts and behaviors.

Between the provided options, the one that matches the principles of cognitive-behavioral therapy is option (d). Aidan's therapist will most likely suggest that he keeps a journal to track his negative thoughts and then works to change those thoughts. Cognitive-behavioral therapy focuses on changing thought patterns and behaviors to improve the symptoms of mental disorders like major depressive disorder.