(A) Each time your ad is displayed on the search results page.
(B) Each time a customer makes a purchase from your website.
(C) When your ad goes live.
(D) Each time a customer clicks your ad.
As the name suggests, with Pay-Per-Click search advertising, you get charged only when someone clicks your ad. The amount you are charged is the bid you set for the keyword which led to the search and the click.
This question is a part of the Bing Accreditation Exam and the Microsoft Advertising Certified Professional exam. You can find all the answers with full explanation for both exams in our Bing Accreditation Exam Answers page and Microsoft Advertising Certified Professional Exam Answers page.