Final answer:
Option (a), The option that is NOT a non-tariff barrier (NTB) is a. a free-trade agreement (FTA), as it aims to reduce trade barriers, unlike the other options which restrict trade.
Step-by-step explanation:
The option that is NOT a non-tariff barrier (NTB) is: a. a free-trade agreement (FTA). Non-tariff barriers (NTBs) are protectionist measures taken by countries to increase the cost or difficulty of importing products into a domestic market.
These include health and safety regulations, import quotas, and government subsidies, which can all restrict international trade by raising the costs or limiting the volume of imports.
However, a free-trade agreement is aimed at reducing or eliminating trade barriers between member countries, thereby encouraging trade rather than restricting it.