Which Scrum event best diagnoses systemic failure to deliver a usable Increment?

Tests whether you map Scrum's empirical pillars to the right event for systemic delivery failure. Strong answer: Sprint Retrospective, because it plans quality and effectiveness improvements by inspecting processes, tools, and the Definition of Done. Contrast with Sprint Review, which inspects the product outcome and adapts the backlog. Red flags: naming Sprint Review, suggesting Daily Scrum is enough, or treating the Retrospective as a blame session rather than an adaptation plan.