Under the Bretton Woods System, Each Currency's Value Was to Be

Under the Bretton Woods system, each currency's value was to be fixed relative to other currencies.What was the mechanism for maintaining these rates?

A) a currency board made up of representatives from all participating nations
B) a currency board made up of representatives from the 12 largest (based on real GDP) participating nations
C) intervention by governments and central banks in the currency market
D) joint intervention by the Federal Reserve of the United States and the British Central Bank