The correct option is Condition.

A Condition on a workflow transition determines whether the transition button is shown on the issue view for a particular user. You can add a condition that checks group membership so only members of the directors group will see the 'Executive Approved' button.

Validator is wrong because validators run when a user attempts to complete a transition and they validate input or block the transition during submission. Validators do not hide or show the transition button on the view screen.

Issue Security Level is wrong because issue security controls who can view the entire issue rather than which workflow transitions are visible on the screen. Changing issue security would affect issue visibility not the transition button visibility.

Post Function is wrong because post functions execute after a transition completes to perform actions like updating fields or firing events. They cannot prevent or hide the transition button before a user clicks it.

Trigger is wrong because triggers automate transitions in response to external events. Triggers do not control whether a user sees a transition button on the issue view.

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