When using location extensions linked through a Google Business Profile, a call button is displayed.

• App
• Reviews
• Products
• Call button

The correct answer is: Call button

Explanation: Location extensions enhance your advertisements by showcasing essential details to guide potential customers to your store. These details can include the address, a map, and the distance to your store. One significant feature of location extensions is the inclusion of a call button or phone number, enabling users to instantly reach out to your business. To activate these extensions, it’s necessary to link a location data source. Google Ads provides two options for this: Google Business Profile for selecting locations from a linked account and Google curated chain for specific store locations without a Business Profile account.

Read more here: https://support.google.com/google-ads/answer/2404182