What does the European Central Bank primarily do within a Monetary Union?

The European Central Bank (ECB) primarily manages monetary policy for the eurozone, which consists of the EU countries that have adopted the euro as their currency. The ECB's main responsibilities include controlling inflation, ensuring price stability, supervising the banking sector, and providing liquidity to the banking system. By setting interest rates and influencing money supply, the ECB aims to support the economic objectives of the eurozone, such as stable economic growth and low unemployment rates.

In a monetary union like the eurozone, individual national economies do not have the ability to regulate their monetary policies independently, as they surrender that authority to the central bank. Therefore, each member country adheres to the monetary policy set by the ECB, making option A the most accurate choice regarding the ECB's primary role. Other options, such as setting trade tariffs or evaluating customer satisfaction, are outside the scope of the ECB’s functions, as those responsibilities are typically handled by different EU institutions or national governments.