Answer:
d. increase the severity of the Great Depression by causing other countries to retaliate, and thus leading to a decline in exports.
Explanation:
Although the main purpose of the Smoot-Hawley Tariff Act was to impose tariffs on imported goods, it followed with reciprocally respond. Since foreign countries were hindered in exporting to the US, they imposed tariffs on the US afterward.
Above all, all economists and historians agreed that this act increased the negative effects of the Great Depression.