(A) Particular buyers in violation of policies
(B) Particular buyers who most recently visited your inventory
(C) Particular buyers who are serving the most popular ads on your site
(D) Particular buyers who are authorized to buy your inventory
Explanation
Each row in the ads.txt file represents particular buyers who are authorized to buy your inventory.
Conclusion
This question is a part of the Check your Knowledge section of the “Create an ads.txt file in Ad Manager” lesson from the “Manage Settings with the Admin Tab” unit which is part of the Drive Advertising Revenue with Google Ad Manager course.