单项选择题 You are trying to bring up a new Testking location onto your existing frame relay network. The new location is using an Adtran router and you are having difficulties getting the site to connect via frame to your Cisco HQ router. What is the most likely cause of the problem?（）

单项选择题 The Testking Central and Remote offices are configured as shown below: The remote router can be successfully pinged from the central office but the remote users cant access the server at the central office.Based on the output above, what do you suspect is the cause of this problem?（）

单项选择题 While troubleshooting a serial line problem, you enable ppp authentication debugging as shown below: Based on the command output above, what type of handshake was used for PPP authentication?（）