You have configured SRST at a remote site on an MGCP gateway. During testing, you find that IP phones are not registering with the SRST router when the IP WAN fails.

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Which three potential problems need to be investigated? (Choose three.)

A.
The ccm-managerfallback-mgcp command is missing in the SRST router.

B.
No SRST reference address is included in the device pool.

C.
The max-dn command is missing in the SRST router.

D.
The max-ephones command is missing in the SRST router.

Explanation: