Under the generalized second price sealed auction mechanism that Google proposed, the participants (advertisers) will pay for each online user’s click on the advertisement of their advertised ad space, and the rule of payment is, .

A、the highest bidder wins the AD space and pays the fee according to his bid;
B、the advertiser who wins the i-th place bid will pay the bid price of the (i+1)-th place bid plus a minimum bid unit (e.g., $0.01);
C、only the highest bidder wins the Ad space, but it pays the second highest bidder's bid;
D、the advertiser who wins the i-th place bid will pay the bid price of the (i+1)-th place bid