(A) Use no more than two extensions per campaign or ad group.
(B) Use at least five extensions and add only to ad groups.
(C) Use ad extensions only when advertising the service industry.
(D) Use at least three extensions in each campaign or ad group.
This question is a part of the Google Ads Search Certification exam. You can find answers to all the questions asked in this exam in our Google Ads Search Certification Exam Answers page.