Refer to the exhibit.

Phones of branch users are not registering to the headquarters Cisco Unified Communications
Manager of 10.10.10.100.
Which action fixes the registration of the branch phones?

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

B.
Add the command ip dhcp excluded-address 10.1.1.1 10.1.1.100.

C.
Change the default-router and network dhcp command setting.

D.
Remove the option 150 command.

Explanation: