- Predictive audiences
- Audience triggers
The correct answer is: User-ID
If you create your own persistent IDs for signed-in users, you can use this data to accurately measure user journeys across devices. To enable the User-ID feature, you must consistently assign IDs to your users and include the IDs along with the data you send to Analytics.
he User-ID feature lets you associate your own identifiers with individual users so you can connect their behavior across different sessions and on various devices and platforms. Analytics interprets each user ID as a separate user, which provides you with more accurate user counts and a more holistic story about a user’s relationship with your business.
Read more here: https://support.google.com/analytics/answer/9213390