A product owner wants to know whether the last release delivered value. Where does the framework say the evidence comes from?

• AFrom observation. The Increment must be usable so that people can react to it, and the Sprint Review is the scheduled point at which the Scrum Team and stakeholders inspect it and discuss what has changed in the environment.
• BFrom the Sprint Retrospective, where the team reflects on how the Sprint went.
• CFrom the estimates the Developers gave, compared against actual effort.
• DFrom the product owner's judgement, since they are accountable for value.