A 32- year- old woman presents to the emergency department, requesting help for back pain. She says that she has wrestled with this pain for 2 years, after a minor skiing accident, and no medications or interventions have helped. No physical evidence explains the degree of pain she reports. The pain prevents her from working as a ballerina. She loves her job but says that for the past few years, budget cuts have stressed the entire ballet company. She denies any problems with sleep, anxiety, or mood. Her body weight is 90% of expected, and she denies any problems with her weight or diet. She is cooperative, and her thought process is linear. What is the likely diagnosis?

A. Adjustment disorder.
B. Anorexia nervosa.
C. Major depressive disorder.
D. Somatic symptom disorder, with predominant pain.