What is viewer's third impression of Trend Takeover+?

The correct answer is "The trend moves down to the Trends section (without the GIF)." This describes the third impression of a Trend Takeover+. After the initial prominent display at the top of the Explore tab with the auto-play GIF and "Promoted by Brand" copy, and the second impression where the GIF disappears but the trend remains at the top, the third impression sees the trend move into the general "Trends for you" section, losing its auto-play GIF and prominent placement. "The auto play GIF for video appears at the top of the Explore tab, with the advertiser's hashtag, trend description, and 'Promoted by Brand' copy" describes the first impression. "An advertiser’s pinned Tweet at the top and a timeline of other Tweets that contain the hashtag is populated" describes a different ad format, not the third impression of a Trend Takeover+.