Which of these must be TRUE for a voluntary exchange to occur? The seller and the buyer must receive equal gains if the transaction occurs. The seller, but not the buyer, must be better off if the transaction occurs. The buyer, but not the seller, must be better off if the transaction occurs. Both the buyer and seller have to be better off if the transaction occurs. lead(s) to efficient production in which each item is produced at the lowest possible cost. Externalities Government intervention Competitive markets Equity