A fixed exchange rate is one that $\_\_\_\_\_.$ A fixed exchange rate is achieved $\_\_\_\_\_\_\_\_\_\_\_\_\_.$

A$.$ Is set by the government or the central bank; by central bank intervention in the foreign exchange market

B$.$ Is determined by demand and supply in the foreign exchange market; with no direct intervention by the central bank

C$.$ Follows a path determined by the government or the central bank by the central bank buying or selling domestic currency in the foreign exchange market

D$.$ Is set by the government or the central bank; by the intervention of market traders in the foreign exchange market