• SUM
• COLLECT
• CONCAT

The correct answer is: CONCAT

Explanation: The CONCAT function in Amazon Marketing Cloud SQL allows you to append (concatenate) a string to fields such as campaign_id, line_item_id, etc. This is useful for ensuring Excel reads large ID fields as strings and preserves their precision and formatting. By concatenating a text prefix or suffix (e.g., CONCAT('camp_', campaign_id)), you avoid Excel’s default conversion of large numbers to scientific notation or truncation.

Official Reference URL: https://advertising.amazon.com/API/docs/en-us/guides/amazon-marketing-cloud/amc-sql/functions#concat