Below is the answer and explanation for the question with TrueView in-stream ads, an advertiser pays: 

With TrueView in-stream ads, an advertiser pays:

• A) On a cost-per-thousand-impressions (CPM) basis
• B) When the viewer watches at least 30 seconds of the video or completes it ✅
• C) Only when the viewer clicks the video
• D) When the viewer watches five seconds of the video

correct answer

When the viewer watches at least 30 seconds of the video or completes it ✅

explanation

In-stream ads run before, during, or after videos on YouTube or on video partner sites and apps. They give viewers the option to skip the ad after 5 seconds. These ads help you drive awareness for your brand and products while people are watching a video. With TrueView ads, you pay when a viewer watches 30 seconds of your video (or the duration if it’s shorter than 30 seconds) or interacts with your video, whichever comes first. This means that you will only pay when someone chooses to interact with your ad.

Read more here: https://support.google.com/adwords/answer/2383007?hl=en

The above answer and explanation are related to Google ads video certification. You can find all the updated questions and answers related to Google video ads certification exam on the “Google ads video assessment answers” page. If you find any error or update in questions or answers, do comment below and let us know. We will update the answers as soon as possible.