Which report in YouTube Analytics provides insight into subscribers and annotation performance?

The Engagements report in YouTube Analytics is the appropriate choice because it specifically focuses on how viewers interact with various elements of your content, such as subscriptions and annotations. This report provides valuable insights into subscriber changes, indicating how well your content is converting viewers into subscribers, as well as tracking the performance of annotations—interactive overlays that link to other pages or videos.

The Engagements report helps you gauge the effectiveness of your strategies in driving viewer engagement. By analyzing this data, you can refine your content and enhance viewer interaction, ultimately contributing to growth in your subscriber base. On the other hand, the other reports listed have different focuses; for example, the View count report primarily tracks the number of views, while the Traffic sources report identifies where your views are coming from, and the Demographics report provides information on the characteristics of your audience. None of these directly assess subscriber behavior or annotation effectiveness in the way the Engagements report does.