Henry Clay believed that his American System with high tariffs on imported goods would benefit the West and South primarily because:
b. He believed Northerners would use their profits to buy goods from the West and South--making money for all.
Clay thought that by protecting northern industries with high tariffs, those industries would thrive and that their increased profits would lead to more trade with the agrarian regions of the West and South, thereby benefiting farmers and contributing to the overall economic growth of the nation.