With a masthead, the advertiser can reserve:
- A) The YouTube homepage.
- B) Specific videos.
- C) Specific channels.
- D) All of the listed answers are correct.
The YouTube Masthead is a customizable 970×250 ad that runs on the top of the desktop YouTube homepage for 24 hours.
Masthead ads are reservation based ads. You can run ads on the YouTube homepage.
Read more here: https://support.google.com/partners/answer/6030919?hl=en