The correct answer is B, because the Sprint Backlog is created during the Sprint Planning meeting. The Scrum Guide states that "the Sprint Backlog is the set of Product Backlog items selected for the Sprint, plus a plan for delivering the product Increment and realizing the Sprint Goal."

According to the Scrum Guide1, the definition of "Done" is a formal description of the state of the Increment when it meets the quality measures required for the product. The definition of "Done" is created by the development organization (or Development Team if none is available from the development organization). The definition guides the Development Team in creating a "Done" Increment.

A Developer is accountable for creating a plan for the Sprint, the Sprint Backlog, and organizing the work required to meet the Sprint Goal, as stated in the Scrum Guide: "Developers are the people in the Scrum Team that are committed to creating any aspect of a usable Increment each Sprint. The specific skills needed by the Developers are often broad and will vary with the domain of work. However, the Developers are always accountable for:
Creating a plan for the Sprint, the Sprint Backlog;
Instilling quality by adhering to a Definition of Done;
Adapting their plan each day toward the Sprint Goal; and,
Holding each other accountable as professionals."