Which of the following correctly describes the behavior of PDO when a database error occurs?

The correct description of PDO's behavior in the event of a database error is that it throws an exception if the error mode is set to exception. This means that when you configure PDO to use exceptions for error handling, any database operation that encounters an error will trigger an exception, allowing developers to catch and handle that exception appropriately.

This feature promotes better error management and debugging practices, as it provides clear indicators of when something goes wrong during database interactions. By enabling the exception mode, developers can implement try-catch blocks around their database code, making it easier to manage errors gracefully and take appropriate actions, such as logging the error or displaying a user-friendly message.

In contrast to this, other options imply behaviors that do not accurately reflect PDO's functionality. For instance, if PDO were to continue execution without interruption, it could result in unexpected behaviors and make debugging very challenging. Automatically reconnecting to the database after an error occurs can also lead to more complex and unpredictable application states. Lastly, PDO does not ignore errors, as this would not provide any feedback on issues that may arise during database operations.