When creating an ad, how does Greg know what it will look like to his potential customers?

Google provides examples of desktop ads using the keywords selected in the campaign to create a generic preview.
Greg can see previews of all his ads by logging into his Google My Business account and choosing the Preview tab.
As he types in his URL, headline, and description, a preview of the mobile and desktop versions of his ad will appear.
Greg must type in the specific keywords he’s targeting once his ad has been approved, then view it in a browser.

The correct answer is:

As he types in his URL, headline, and description, a preview of the mobile and desktop versions of his ad will appear.