A Copilot Studio agent at Wide World Importers crashes unexpectedly due to an unhandled exception not caught by any action node's OnError path. The current behavior is to display a generic platform error. The team wants a custom branded error experience. Which Copilot Studio configuration addresses this?

## Why B is Correct Copilot Studio has a built-in Error system topic that fires when an unhandled exception occurs anywhere in the agent's execution and is not caught by a topic-level error handler. By customizing this system topic, developers can replace the generic platform error with a branded message, an offer to escalate to a human agent, a suggestion to try again, or any other desired recovery experience.

## Why the Distractors Are Wrong A (Fallback topic): The Fallback system topic fires when no topic matches the user's utterance — not when a runtime exception occurs. These are distinct system topics with distinct triggers.

C (Try/catch in every flow): Wrapping every flow in error-catching logic is defensive programming at the flow level, but it does not address exceptions that occur in topic logic, condition nodes, or other non-flow elements. It is also impractical to wrap every action node.

D (Webhook for monitoring): A monitoring webhook is valuable for observability but is not a user-facing error experience. It does not replace the error message seen by the user.

## Exam Tip System topic mapping: Fallback = no intent match. Error = unhandled runtime exception. Escalate = explicit escalation trigger. End of Conversation = conversation closing. Know which system topic to customize for which scenario.