What is NOT a source of the EU budget?

The correct answer highlights that road fees do not contribute to the EU budget. The European Union primarily generates its budget from a few specific sources. These include contributions based on the value-added tax (VAT) collected by member states and a percentage of the gross national income (GNI) of those states.

The use of government bonds, while relevant in other contexts like financing projects or managing debt, does not play a role in financing the core budget of the EU. Therefore, it is not considered a source of income for the EU's operational budget.

Understanding the structure and the types of revenues that fund the EU budget is crucial for recognizing the financial framework of the EU, which is designed to promote its objectives and manage its policies effectively.