Which of the following is NOT an example of a brand safety provider?

Ads.txt is a tool primarily focused on combating ad fraud by allowing publishers to declare which companies are authorized to sell their digital advertising inventory. It acts as a transparency initiative to prevent unauthorized advertising and provides a way for advertisers to verify the legitimacy of inventory being sold. This is distinctly different from the functions of brand safety providers, who focus on ensuring that ads are appearing in appropriate contexts, thereby protecting a brand's reputation and avoiding association with undesirable content.

In contrast, the other options—DoubleVerify, Integral Ad Science, and Ghostery—are examples of brand safety providers. These companies offer services that assess and provide insights concerning the contexts in which advertisements appear, ensuring that brands are protected from reputational risks by avoiding placements next to harmful or inappropriate content.