The correct option is Issue assigned because assignment changes are not provided as a built in default project workflow trigger in GitHub Projects.

GitHub Projects includes default workflow triggers for common item and pull request events so items can move or update automatically without custom automation. These include item state changes such as when an item is added to a project, reopened, or closed, and pull request events such as review approvals or changes requested. There is no default trigger for assignment changes, so Issue assigned does not appear in the built in list.

Item reopened is available as a default trigger and can be used to update fields or move an item when an issue or pull request is reopened.

Auto-archive items is a built in workflow that automatically archives items after a period of inactivity based on the configuration you choose.

Code review approved is covered by the default trigger for pull request reviews that are approved, which can update project fields or move items when a review approval occurs.

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