One factor the AdWords system uses to calculate an ads actual cost-per-click (CPC) is the:

One factor the AdWords system uses to calculate an ads actual cost-per-click (CPC) is the:

A) actual cost-per-click (CPC) of the ad showing one position lower on the page 
B) location targeting of the ad showing one position lower on the page
C) cost-per-thousand impressions (CPM) of the ad showing one position lower on the page
D) Ad Rank of the ad showing one position lower on the page