Blockage is ideally accomplished:
A. when a country refuses to allow an importer to exchange its national currency for the seller's currency.
B. when two countries enter into a voluntary agreement to restrict volume of exports.
C. when a country applies specific unit or dollar limit to a particular type of good.
D. when countries limit the export of certain goods on a case-by-case basis.
E. when the government imposes a mandatory tax on goods entering at its borders.
Answer: A. when a country refuses to allow an importer to exchange its national currency for the seller's currency.