The question asks for the term used for the amount charged by customs on imports.
- (a) Tariff: A tariff is a tax or duty imposed by a government on goods imported into a country (import tariff) or, less commonly, exported from a country (export tariff). Tariffs are a form of trade barrier and can be used to raise revenue for the government or to protect domestic industries from foreign competition. The term "tariff" specifically refers to these customs duties on international trade.
- (b) Export duty: This is a tax specifically on goods being exported out of a country. The question refers to imports.
- (c) Charges: This is a very general term. While tariffs are a type of charge, "charges" itself is not specific enough to define customs duties on imports. There can be various other port charges, handling charges, etc.
- (d) MFA (Multi-Fibre Arrangement): The Multi-Fibre Arrangement (1974-2004) was an international trade agreement that imposed quotas on the amount of textiles and apparel that developing countries could export to developed countries. It was about quantity restrictions (quotas), not directly about taxes/duties (tariffs), although tariffs also existed. MFA has now expired and been replaced by WTO Agreement on Textiles and Clothing.
The most accurate term for the amount charged by customs imposed on imports is
Tariff (specifically an import tariff or import duty). \[ \boxed{\text{Tariff}} \]