Which of the Following Make Assessment of Persistent Depressive Disorder

Which of the following make assessment of persistent depressive disorder (PDD) a difficult task? (choose all that apply)

A) Many methods refer to differences from "normal" or "usual" state, which is often a depressed state for these patients.
B) Difficult to assess course using current assessment methods (e.g., structured interviews, rating scales, self-reports) .
C) There are no rating or self-report scales developed specifically for chronic mood disorders.
D) Using DSM-5, it is difficult to distinguish between PDD and MDD.