When the currency of another country circulates as the sole legal tender
B.
When the country belongs to a monetary or currency union in which the same legal tender is shared by the members of the union.
C.
A monetary regime based on an explicit legislative commitment to exchange domestic currency for a specified foreign currency at a fixed exchange rate, combined with restrictions on the issuing authority to ensure the fulfillment of its legal obligation.
D.
Where the country pegs its currency at a fixed rate to a major currency where the exchange rate fluctuates within a narrow margin of less than one percent.