Why would you want to review the ratio of views being converted to ads?

To see how the ad rates are affected by viewer engagement.
To see the approximate ratio of how many views resulted in an ad being served and how it is trending over time.
To see which type of ad brought in the most revenue.
To see the actual number of subscribers that watched the ad and commented on the video.

The correct answer is:

To see the approximate ratio of how many views resulted in an ad being served and how it is trending over time.