_________ are optional, clickable thumbnail images that accompanies TrueView in-Streamad.
- Companion banners
- TrueView in-display ads
- YouTube Mastheads
- Companion Mastheads
Explanation:
Companion banner is a clickable thumbnail image that accompanies a TrueView in-stream ad. On a YouTube page, it appears next to the ad, in the top right corner (on a desktop computer). A companion banner provides continued brand presence after a video ends, and the viewer can click on it anytime. There are two kinds of companion banners: image and video wall.
A clickable thumbnail image that accompanies a TrueView in-stream ad. On a YouTube page, it appears next to the ad, in the top right corner (on a desktop computer).Companion banners are optional. They’re also displayed only in certain cases, for example, in the context of a YouTube watch page. They don’t show on embedded players, connected TVs, or game consoles.
Read more here: https://support.google.com/partners/answer/6293542?hl=en