What achievement had America achieved over the last 80 years according to President Polk's speech 1845?

Polk accomplished nearly everything that he said he wanted to accomplish as President and everything he had promised in his party's platform: acquisition of the Oregon Territory, California, and the Territory of New Mexico; the positive settlement of the Texas border dispute; lower tariff rates; the establishment of a .. pls mark me branilest

answer; ///i believe that the correct answer is (a) the great depression