The abolition of all forms of trade barriers among member countries while maintaining common external tariffs against non-members is a feature of a?

A. free trade
B. custom union
C. common market
D. economic union

Correct Answer: Option D

D. economic union

Explanation

An economic union is an agreement between two or more nations to allow goods, services, money, and workers to move over borders freely. The countries may also coordinate social and financial policies to support this common market.