An entity conducts trade transactions in country A, its currency is the dollar. After several years, the entity expands and exports its products to country B, its currency is the euro. This business is conducted through a subsidiary of an entity in country B. The subsidiary is basically an extension of the entity's own business, and the directors of the two entities are the same. The functional currencies of subsidiaries are: A.Dolar. B.Euro C.Dollar or Euro D.Difficult to determine