Sprint retrospective is the correct answer. To gather lessons learned and look for improvement opportunities, a sprint retrospective should be held after a sprint review but before a sprint planning meeting. This activity allows the team
to consider feedback from the owner, and also implement improvements before the next sprint. The other answers are incorrect: product backlog refinement occurs in product refinement meetings; sprint planning meetings take place after
the product refinement meeting; the Daily Scrum is hosted every day at the same time and same place.