Viewable impressions:

  • A) Allow you to only pay for those ads that are actually viewed
  • B) Allow you to pay for ads when they are displayed in a viewable position
  • C) Allow you to only pay for video ads that are viewed within an hour
  • D) Allow you to pay for ads that are viewed and also converted

The correct answer is:

  • B) Allow you to pay for ads when they are displayed in a viewable position

Explanation: With vCPM bidding, you bid for your ad based on how often it appears in a viewable position on the Google Display Network.

Read more here: https://support.google.com/adwords/answer/2630842?hl=en