The world's largest exporter of immigrants.

Analysis of test questions: Pay attention to the time of "1932", which coincides with the great crisis of western capitalist economy and the surge of unemployment; However, the Soviet Union was not affected by the economic crisis. 1932, the first five-year plan was completed and great achievements were made in economic construction, which became the main reason for Americans to apply for immigration to the Soviet Union. Therefore, it is obviously wrong to choose items A and B. Roosevelt just took office 1932. Item c is wrong. Relations between the United States and the Soviet Union eased during World War II. Item d is obviously wrong.

Comments: During Stalin's period, the Soviet Union gradually abandoned Lenin's new economic policy and established a planned economic system through agricultural collectivization and industrialization. In the economic crisis of the western capitalist world, the Soviet Union has not been affected, and its economic construction has made great progress, thus attracting more foreigners, including Americans, to immigrate to the Soviet Union.