Concept:Trade barriers are used by governments to restrict imports and support domestic industries.Explanation:One major reason for erecting trade barriers is to protect infant industries from foreign competition.New or growing domestic firms may not yet be efficient enough to compete with established foreign producers.Barriers such as tariffs and quotas give these young industries time to develop and become competitive.Controlling foreign currencies, promoting importation, or diversifying the economy are not typical aims of trade barriers.Answer:B. protect infant industries