As part of the nation’s recovery from the Great Depression of the 1930's, the banking system was taken off the gold standard. Option D is correct.
The Great Depression began in the United States and it constituted a severe worldwide economic depression that took place mostly during the 1930s.
The Great Depression started as a major fall in stock prices that began around September 4, 1929, and turnt into worldwide news with the stock market crash of October 29, 1929.