Final answer:
Dr. Randell, who recommends behavioral modification programs to help clients quit smoking, is likely a behavioral psychologist, employing evidence-based techniques to facilitate behavior change and relapse prevention.
Step-by-step explanation:
Dr. Randell is most likely a behavioral psychologist. Behavioral psychologists focus on behavior modification programs to help clients change unhealthy behaviors. They utilize evidence-based practices such as self-monitoring, education, and setting physical activity goals to help individuals initiate and maintain behavior changes, like ceasing to smoke. Despite awareness of the dangers of smoking, smokers often benefit from strategies that encompass not just decisions about what to change but specifically how to change. These interventions are typically comprehensive and may span several years, with the goal being not only to stop the unwanted behavior but to prevent a relapse.