Which of the following can you display by clicking User Reports > Top N in the UCM 8.0 CAR GUI?

A.
the top number of billing errors

B.
the top call volume for a given period of time

C.
the top QoS rating information for inbound calls

D.
the top number of users by maximum length of calls

Explanation:
You can display information about the top number of users by maximum length of calls by using the User
Reports menu. The By Duration report can be accessed by clicking User Reports > Top N in the Cisco Unified
Communications Manager (UCM) Call Detail Records (CDR) Analysis and Reporting (CAR) graphical user
interface (GUI). This report enables a CAR administrator to view users who have made the longest calls over a
given period of time, starting with the user who placed the longest call.
You can view information about the call volume for a given period of time by using the System Reports > Traffic
> Summary by Phone Number report in the UCM CAR GUI. This report enables a CAR administrator to choose
a range of time and IP phone extension numbers from which to view call volume information, thereby enabling
an administrator to view what extensions were in use at a specific time.
You can view information about the current number of billing errors by using the System Reports > CDR Error
report in the UCM CAR GUI. This report enables a CAR administrator to view the number of errors that
occurred when CDR data was loaded into the reporting system.
You can view Quality of Service (QoS) rating information for inbound calls by using the System Reports > QoS
> Detail report in the UCM CAR GUI. The Detail report enables a CAR administrator to choose a UCM network
and a period of time for which to view QoS ratings for both inbound and outbound calls. The Detail report can
be used to monitor QoS at a user level.

Cisco: Understanding CAR System Reports: System Reports Summary Description
Cisco: Configuring Traffic System Reports: Configuring Traffic Summary by Phone Number Reports