How does the Choice router work in a Mule flow?

• A. The Choice router evaluates when-conditions in order and routes the message to the first matching route; an otherwise block handles unmatched cases.
• B. The Choice router routes the message to all routes simultaneously.
• C. The Choice router routes messages based on hash of payload.
• D. The Choice router is used to split a message into separate parts with parallel routing.

Answer: (B)

The Choice router in a Mule flow acts like an if-else ladder. It evaluates each when expression in order and sends the message down the first branch whose condition is true. If none of the when conditions match, an otherwise block can provide a default path. Importantly, only one branch is taken, not multiple in parallel. You can write when expressions that inspect the payload, attributes, or variables, for example checking payload type or a property value. After the chosen route finishes, control returns to the flow after the Choice. This makes Choice a straightforward way to implement conditional routing based on the message content.