Answer: A. Canada.
Step-by-step explanation:
Out of the list provided, Canada is the United States’ largest trading partner. However, since 2015 China excelled Canada as the most prominent U.S. trading partner. According to the U.S. Census Bureau, that tracks U.S. imports and exports on a monthly basis, by 2017 America’s top trading partners were China, Canada, and Mexico, in that order. So far in 2019, China is still at the top with 16% of total trade. Next comes Canada (15%) and Mexico (15%).