Many countries engage in trade protection by imposing import tariffs or quotas for at least some goods. this is because: a. while such restrictions harm consumers, they benefit producers who are usually a more cohesive and politically influential group. b. economists have established that such restrictions are welfare-improving for certain categories of goods (such as raw materials). c. while such restrictions harm consumers and benefit producers, the losses to consumers are outweighed by the gains to producers. d. such restrictions tend to benefit consumers without harming producers.