In order to appeal to customers on mobile devices, it’s important to:

 

• Send users to a video-based landing page
• Send users to a mobile-friendly landing page
• Avoid using ad extensions
• include your phone number as your display URL

Correct answer is:

• Send users to a mobile-friendly landing page

 

 

Read more here: https://support.google.com/adwords/answer/1704392?hl=en