To recognize users across different devices, what feature must be enabled?User IDGoogle Ads LinkingAttribution ModelsAudience Definitions

To recognize users across different devices, the feature that must be enabled is User ID.

Explanation

The User ID feature allows for the association of multiple sessions and any activity from a single user across different devices. By implementing User ID, you create a more seamless experience for users who may switch between devices, ensuring that you can track their interactions accurately. This feature enhances tracking precision and provides rich insights into user behavior, ultimately improving attribution and analytics.

In contrast, Google Ads Linking, Attribution Models, and Audience Definitions are important components of digital marketing and analytics but do not specifically address cross-device user recognition.