An IP phone has a line calling search space and a device calling search space. If a call is made
from the IP phone, which calling search space is used?

A.
Neither calling search space is used.

B.
The line calling search space takes precedence and is used.

C.
The device calling search space takes precedence and is used.

D.
The line and device calling search spaces are combined and the line calling search space has
precedence.

Explanation:
If you configure a calling search space both on an IP phone line and on the device
(IP phone) itself, Cisco Unified Communications Manager concatenates the two calling search
spaces and places the line calling search space in front of the device calling search space
Link: http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/8_0_2/ccmsys/a03ptcss.html