You have configured the following：  RMAN> CONFIGURE DEFAULT DEVICE TYPE TO ’sbt’； new RMAN configuration parameters：  CONFIGURE DEFAULT DEVICE TYPE TO ’sbt’； new RMAN configuration parameters are successfully stored RMAN> SHOW DEVICE TYPE； RMAN configuration parameters are： CONFIGURE DEVICE TYPE SBT PARALLELISM 1； # CONFIGURE DEVICE TYPE DISK PARALLELISM 1； #  RMAN> CONFIGURE DEVICE TYPE SET PARALLELISM 5；  RMAN> SHOW DEVICE TYPE； RMAN configuration parameters are： CONFIGURE DEVICE TYPE SBT PARALLELISM 5； CONFIGURE DEVICE TYPE DISK PARALLELISM 1； #  How many channels are allocated to SBT？（）

• A、0， because channels have not been defined.
• B、3， as indicated by the degree of parallelism.
• C、1， the default value when device is configured.
• D、5， as indicated by the last parallelism command.