Final answer:
The 38% tariff on Canadian softwood imports reduced competition for US softwood producers (option A), who are the ones that benefitted from this tariff by being able to raise their prices due to less competition.
Step-by-step explanation:
The United States has imposed a 38% tariff on softwood imports from Canada. As a result of this tariff, imports of lumber from Canada decreased sharply and the price of lumber in the U.S. market rose significantly. The group that benefited from this tariff would be A. US softwood producers. This is because the tariff made imported Canadian lumber more expensive, reducing competition for U.S. producers and allowing them to raise their prices. Consumers in the U.S. had to pay more for lumber, and Canadian producers faced decreased sales due to their products' increased prices in the U.S. market.
Non-Canadian foreign producers (C.) could potentially benefit if they were not subject to the same tariffs and could compete at lower prices than the tariffed Canadian lumber. However, the question does not present enough information to determine if that was the case.