Answer:
B, Customs union.
Explanation:
A customs union is defined as a trade bloc that has a free trade area, where countries with trade pacts have a common external tariff.
Customs union cannot be created without a trade pact and it is usually between two or more countries. This union means that countries with the trade pact between one another can bring in or take out their goods into those countries at a tariff that is lower compared to other countries that have no trade pact with the country or countries.
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