which of the following statements is true? a. economic efficiency would be increased if the united states eliminated all of its trade restrictions, but only if all other countries eliminated their trade restrictions too. b. the u. s. economy would gain from the elimination of its tariffs but not from the elimination of its quotas. c. eliminating its tariffs and quotas unilaterally would not benefit the united states because this would remove the leverage it would have to persuade other countries to eliminate their trade restrictions. d. the u.s. economy would gain from the elimination of tariffs and quotas even if other countries do not reduce their tariffs and quotas.