Error handling can be triggered by which of the following?

Error handling in Mendix can be triggered by both user actions and system events, making the correct answer one that encompasses both sources of potential problems.

User actions might include activities such as submitting a form, clicking a button, or inadvertently inputting invalid data. These actions can lead to errors that need to be captured and managed effectively to ensure a smooth user experience. When a user performs an action that results in an error, the application's error handling mechanisms can provide feedback, log the error, or even redirect the user to ensure they can continue using the application without disruption.

On the other hand, system events refer to errors that might occur due to underlying processes or system-level issues, such as database connection failures, timeout errors, or problems with external services. These system-generated errors can also trigger error handling processes, which helps maintain the application's robustness and reliability.

This dual capability of error handling is essential for creating a resilient application, as it ensures that both user-induced and system-induced errors are appropriately managed. Other options focusing solely on user actions or system events would not cover the full spectrum of possible error triggers, leaving gaps in the application's error management strategy.