D is correct. Ignore my other comment.

A is correct according to official practice exam

If a JMS broker is not available the JMS consume operation of JMS connector will throw connection error. With option A, when consume fails the control goes to on error continue and go to subsequent step which will again fail. In case of option B, the connector will keep failing and filling up the logs until the operation is successful. This will work but not an effective solution. There is no point of creating a transaction and rollback on failure because both the destinations are on same broker. Also, it will rollback and will not reconnect. Reconnection strategy, however, will try to reconnect after a regular interval and the consume will not poll for a message till the connection is established. This surely is a more elegant way to handle the error and establish the connection again.

D. Configure a reconnection strategy for the JMS connector

Should be D. Reconnect setting will allow mule to reconnect after JMS broker outage. Cannot be A, B or C because in all of those scenarios, mule flow will throw an error and fail rather than recover.

D is correct