• Display ads with location extensions
• Lightbox ads
• TrueView ads
• Universal app campaigns

The correct answer is: Universal app campaigns

Explanation: As an app advertiser, you want to get your app into the hands of more paying users.  If your goal is to find more valuable users, and you have the key in-app action tacked as a conversion event, use this option. AdWords will focus on people who are most likely to complete the specific in-app actions you’ve set up and selected for this campaign.
Read more here: https://support.google.com/google-ads/answer/6247380