Refer to the exhibit.

When the WAN link to headquarters fails, phones of the branch users are registered to the SRST
gateway but cannot successfully dial 911 to the local Public Safety Answering Point.
Which action enables 911 dialing to the PSAP when the WAN link is down?

A.
Add the command MGCP.

B.
Add the command prefix 911 to dial peer 911.

C.
Add the command ccm-manager redundant host 10.10.10.101.

D.
Add the command telephony-service and configure Cisco Unified Communications Manager
Express to the existing configuration.

E.
Dialing to the PSAP is not possible when the WAN link is down.