Drew is selling math textbooks and using cost-per-click (CPC) bidding for his campaign. What’s the final cost each time his ad is clicked?

Drew is selling math textbooks and using cost-per-click (CPC) bidding for his campaign. What’s the final cost each time his ad is clicked?
§  The projected maximum cost-per-click (max. CPC)
§  The average amount charged each time someone clicks on his ad
§  The average amount needed to make the ad appear somewhere on the page

§  The minimum amount needed to maintain a higher rank than the rank held by the next-highest bidder in the auction