Answer:
d. It was an earlier form of the European Union and was smaller.
Step-by-step explanation:
The Common Market was the parent form of what is known as the European Union, and worked like the N.A.F.T.A treaty which was signed by the U.S., Canada, and Mexico. What both of these treaties essentially did was to open "free trade" in between all signers of the treaty, in which no duty (or taxes) are placed on designated or even all products in between the countries.
The E.U. replaced the Common Market by giving the European countries a stronger currency, also known as the Euro, and combined the military strengths of Europe to make a stronger military bloc for defense or when needed.
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