None of these callbacks will be called when is_admin is true. [Explanation]: When saving the User model and model.is_admin is set to true, the after_save callback will be called. The before_save callback with the unless: ->(model) { model.is_admin } condition will not be called because the is_admin attribute is true. The before_destroy callback with the if: ->(model) { model.is_admin } condition will be called if the is_admin attribute is true and the record is being destroyed, but this is not relevant to the scenario of saving the User model. Therefore, only the after_save callback with the if: ->(model) { model.is_admin } condition will be called in this scenario. This callback will be triggered after the record has been saved, if the is_admin attribute is true. In this case, the clear_cache method will be called.