(A) To see which type of ad brought in the most revenue.
(B) To see the effect of viewer engagement on ad rates.
(C) To see how this ratio is trending over time.
(D) To see how many subscribers watched the ad and commented on the video.
You might want to review the ratio of views to ads shown on a video in two time periods in order to see how this ratio is trending over time.
This question is a part of the YouTube Music Assessment. You can find answers to all the questions asked in this exam in our YouTube Music Assessment Answers page.