Which of the Following Best Reflects Psychology's Goal of Explanation

Which of the following best reflects psychology's goal of explanation?

A) Researchers have developed a test that shows whichdividuals are likely to develop Alzheimer's disease.
B) Researchers have studied how smoking habits develop so that they may develop techniques to prevent teenagers from starting the habit.
C) Researchers have identified a genevolved many cases of obesity
D) Researchers have examined hundreds of cases of dissociative identity disorder (multiple personality) order to provide a clear picture of the disorder.