• campaign
• supply_source
• user_id

The correct answer is: campaign

Explanation: The correct answer campaign refers to the campaign field (which holds the campaign name) available in the sponsored_ads_traffic (and similar) event tables within Amazon Marketing Cloud, as explicitly documented in the official Amazon Ads documentation for the Sponsored Ads traffic data schema.

Reference: https://advertising.amazon.com/API/docs/en-us/guides/amazon-marketing-cloud/datasources/sponsored_ads_traffic