In which cities are EU institutions located?

The correct answer identifies cities that are home to major European Union institutions. Brussels is the primary location for key EU bodies, including the European Commission and the Council of the European Union. Luxembourg City houses the European Court of Justice and various administrative offices, while Strasbourg is known for hosting the European Parliament. Frankfurt, while significant in its own right as a financial hub and location for European Central Bank activities, is not an official seat of a major EU institution, making it a less relevant inclusion compared to the other cities mentioned in the correct answer.

This combination of cities is well-established as the administrative and legislative heart of the European Union, providing the necessary infrastructure and environment for EU operations. Other answer choices included cities that either do not host EU institutions or have a less central role in EU governance. For instance, some cities listed might be important in other contexts but do not function as official locations for EU decision-making processes or institutions.