A gynecologist refers a 32- year- old hospital employee to a psychiatry clinic, noting that the pt requested testosterone shots and also a surgical referral. From the past medical records, the psychiatrist learns that the pt has normal female development and anatomy with no known abnormalities. The pt wears bland- colored baggy clothing, has very short hair, and goes by the name "Jo". She is initially brief with her answers but, after some time, is tearful, explaining that she has never been comfortable as a woman and is positive she is "supposed" to be a man. She feels ostracized at work and isolated socially. She has feelings of low self- worth and some depressed mood. What is the likely diagnosis?

A. Adjustment disorder.
B. Anorexia nervosa.
C. Depersonalization/ derealization disorder
D. Gender dysphoria in adolescents and adults.