The correct answer is D. A diagnostic labeling effect
Explanation:
In psychology, a diagnostic labeling effect occurs when the diagnostic label or name to classify an individual's condition, illness or mental disorder lead to stigma or stereotypes which means is used by other individuals that are usually not doctors or experts in health to create biased perceptions or dies. This effect is the one that takes place in the example presented because, in this, the diagnostic label "depression" was used to explain the candidate's behavior although many other candidates had the same behavior, which implies the label led to stigmas about the politician, which occurs in the diagnostic labeling effect.