Which of the Following Could Be Considered a Cause of the Collapse

Which of the following could be considered a cause of the collapse of the Bretton Woods system?

A) The existence of Japanese budget deficits offset currency reserves as the yen become increasingly overvalued.
B) The United States gold stock became increasingly too small to meet foreign dollar liabilities.
C) Countries in Europe devalued currencies to increase export competitiveness.
D) In order to meet reserve requirements imposed by the IMF, France and Germany mandated private holders of gold to purchase U.S. dollars destabilizing the U.S. dollar to gold peg.