What is an example of a non-tariff barrier?

A non-tariff barrier is a restriction that countries employ to control the amount of trade across their borders without imposing a direct tax on imports or exports. Quotas are a prime example of this as they limit the quantity of a specific product that can be imported or exported during a given timeframe. By establishing quotas, a country can protect its local industries, regulate supply, and influence prices in the market without levying tariffs.

The other options provided, such as income tax rates, value-added tax, and sales tax, are forms of taxation. These taxes could affect the overall economic environment and consumer purchasing power but do not fit the definition of non-tariff barriers because they do not directly limit the quantity or flow of specific goods across borders. Instead, they impact the cost structure and profitability of businesses and consumers in ways that are not equivalent to introducing quotas on trade.