The Definition of "Done" ensures quality and clarity. The Scrum Guide states: "The Definition of Done

is a formal description of the state of the Increment when it meets the quality measures required for

the product."

A: It ensures the Increment is usable/releasable: "In order to provide value, the Increment must be

usable."

B: It provides transparency by setting a shared standard: "The Definition of Done creates

transparency by providing everyone a shared understanding of what work was completed."

C: The Sprint Goal is separate, defined in Sprint Planning.

D: Unit testing is a practice, not a purpose of "Done."

Exact Extract from Scrum Guide: "The Definition of Done creates transparency by providing everyone

a shared understanding of what work was completed as part of the Increment... In order to provide

value, the Increment must be usable." (Section: "Definition of Done")

Thus, A and B are correct.

Reference: Scrum Guide (2020), Section: "Definition of Done."