Which of the following is NOT a subfield of psychology?

Historical psychology is not recognized as an official subfield of psychology in the same way that the others listed are. Clinical psychology focuses on diagnosing and treating mental health issues, while health psychology examines how psychological factors influence physical health and wellness. Industrial/organizational psychology applies psychological principles to workplace environments, enhancing productivity and employee well-being. While understanding historical perspectives is important in psychology, it does not constitute a distinct subfield. Therefore, it stands out from the other choices as it lacks the specific focus and application associated with recognized areas of psychological practice.