can someone help me with this question please

The following table displays the reservation values of eight buyers and eight sellers, who each want to buy or sell a calcuiator. You are in charge of deciding which buyer trades (or not) with which seller at what price as you see fit. You could prescribe different prices to each pair of a buyer and a seller. Refer to the table above. Suppose you decided that Buyer 1 and Seller 1 trade at the price that is exactly halfway between the reservation values. Also Buyer 2 and Seller 2, Buyer 3 and Seller 3 , Buyer 4 and Seller 4 and Buyer 5 and Seller 5 do the same The outcome will be Buyer has the largest net benefit of has the smallest net ben of efficient: 1; \$18; 5;$0 inefficient; 1:$12;5:$12 efficient; 1;$9;5;$0 efficient; 1;$18;5:$12