The Definition of Done is a shared understanding of what it means for work to be complete, and ensures transparency of the quality of the work done1. A Product Backlog item is considered complete when it meets the Definition of Done, which means that it is usable and potentially releasable, and that it meets the quality standards set by the Scrum Team and the stakeholders2. The other options are not sufficient to determine the completeness of a Product Backlog item, as they may not reflect the actual value and quality of the product.
References:
1: The Scrum Guide, November 2020, p. 13
2: The Scrum Guide, November 2020, p. 6