Explanation:

- Corporation Tax: This is a tax imposed on the income or profits of corporations and businesses. It is not related to the import or export of goods.

- Excise Tax: This tax is levied on the production and sale of specific goods within a country. It is not directly associated with imports or exports.

- Capital Gains Tax: This tax is applied to the profit derived from the sale of assets or investments. It is unrelated to trading goods cross-border.

- Custom Duty: This is the tax imposed on goods imported into or exported out of a country. It is specifically related to trade and customs processes.

Correct Answer: Custom Duty