Key goals of the burndown chart in Agile project delivery include:

C. Visualization of the size of the backlog consumed so far: The burndown chart provides a visual representation of work completed over time against the total work scope, helping teams track progress and pace.

D. Determination of the planned go-live date based on current velocity: By analyzing the rate at which the team is completing work, project managers can forecast when the project is likely to be completed, which aids in planning for the go-live date.

Options A (Determination of the overall availability of the team for the future sprints) and B (Assignment of backlog items to future sprint up to completion of the release) are not direct goals of the burndown chart; these aspects are more related to sprint planning and capacity management.References:

Agile project management tools and their uses

Effective use of burndown charts in project management

Agile Project Delivery