The Smoot-Hawley Tariff Act of 1930 a. ​resulted in foreign nations increasing their tariffs on U.S. export b. ​decreased U.S. tariffs to the lowest level since the early 1800s c. ​increased U.S. tariffs to an average of 53 percent on protected imports d. ​decreased U.S. tariffs to the lowest level since the late 1800s