The administrator is unable to establish connectivity between two Cisco routers. Upon reviewing
the command output of both routers, what is the most likely cause of the problem?

A.
Authentication needs to be changed to PAP for both routers.

B.
Username/password is incorrectly configured.

C.
Router names are incorrectly configured.

D.
Serial ip addresses of routers are not on the same subnet.

Explanation:
When configuring for CHAP authentication, you must enters the other router’s user name and
password. In this case on router RtrB has entered incorrect router RtrA password, witch is “cisco1”
(it must be “cisco”). As a result CHAP authentication will fail, therefore the connection
establishment between the routers will be refused.
Reference: CCNA Self-Study CCNA ICND Exam Certification Guide Chapter 9 page 315 ISBN: 1-
58720-083-x