This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Mood Disorders, Subject name: Psychiatry
A 25-year-old man presents to the outpatient department with the complaint that he has been depressed ever since he can remember. In addition, he also has disturbance in sleep and appetite. However, he has been working, though not to the level of satisfaction of him or his supervisors. The patient also has general dissatisfaction with life. The most likely diagnosis is: 
Select and explain. 
A. Major depression, B. Psychotic depression, C. Dysthymia, D. Chronic fatigue syndrome
C: Dysthymia
Answer: C: Dysthymia 
Explanation: Ans. C. DysthymiaDysthymia: it's presence of mild depressive symptoms (not enough to diagnose a MDD) for a period of at least 2 years - socio-occupational dysfunction is not markedIn DSM-5: persistent depressive disorder (clubbed chronic depression + dysthymia)