Dean has a comprehensive final exam in three weeks that he is concerned about. His concerns prompt him to go ahead and start studying, and in doing so, he feels less worried as the exam approaches. In this example, the exam, Dean’s concerns, and his behavior may be seen as an example of .

eustress

Explanation:

Eustress: In psychology, the term "eustress" is described as "beneficial stress" and it can either be radiological, biochemical, or physical, psychological.

In other words, eustress is determined as an individual's positive feelings or response towards specific stressors and it entirely depends on his or her ongoing feelings of location, control, desirability, and the timing of specific stressors.

In the question above, the exam, Dean’s concerns, and his behavior may be seen as an example of eustress.