What is the most common form of trade barrier?

• A. A tax on exports used to raise revenue.
• B. A tariff, a tax on imports.
• C. An agreement to reduce tariffs.
• D. A currency exchange mechanism.

Answer: (B)

Tariffs, a tax on imports, are the most common form of trade barrier. By making imported goods more expensive, they reduce foreign competition and help domestic producers. Tariffs are straightforward to implement at the border and not only protect local industries but also generate government revenue, which is why they’ve been widely used across many economies. Other options—taxing exports, which would curb outbound trade; agreements to reduce tariffs, which loosen barriers; and currency mechanisms, which facilitate exchange—do not function as barriers in the same way.