The correct answer is: User
User scope: Create user-scoped custom dimensions to identify static or slowly changing attributes of your users, such as “spender=true”, “profession=engineer”, or “favorite_team=Real Madrid”.
Read more here: https://support.google.com/analytics/answer/10075209
User or session-scoped custom dimensions will not be filtered even if the hit they were attached to is filtered. Their values will still be applied to all hits in the current session, as well as future sessions if the dimension has user scope.
Read more here: https://support.google.com/analytics/answer/2709828