Which three of the following are time-boxed events in Scrum?

 According to the Scrum Guide, the time-boxed events in Scrum are Sprint Retrospective, Sprint Planning, and Daily Scrum. These events have a maximum duration that cannot be exceeded. The other options are not time-boxed events in Scrum, as they are either not part of Scrum (such as Release Planning, Release Retrospective, Sprint Testing, and Sprint 0) or not events at all (such as Definition of Done).