During an engagement with a sidekick ad, how does the ad typically extend?

The correct answer indicates that a sidekick ad typically extends to the side of the page. Sidekick ads are designed to be integrated alongside primary content on a webpage, allowing them to be more engaging without disrupting the user experience. By extending to the side, these ads can capture attention while still allowing users to interact with the main content. This positioning takes advantage of the natural scanning patterns of users, who often begin at the top of a page and move downwards while still being aware of any content located to the side.

This format contrasts with other options that imply different placements or styles of advertisement. For instance, the dropdown menu option would suggest a type of interaction that isn’t characteristic of sidekick ads, which typically interact more directly with the main page content. Extending to the bottom or across the entire banner space would also not fit the definition since such placements would dominate more of the screen or disrupt the user's ability to access other content. The side extension effectively enhances visibility without overwhelming the user experience, making it the defining characteristic of sidekick ads.