单项选择题

A. The IP addresses are configured incorrectly.
B. Frame Relay LMI messages not displayed in real time.
C. The administrator must issue the enable frame-relay lmi debug command.
D. The administrator must issue the terminal monitor command.
E. Debug messages can only be received once through the console port.
F. The administrator must issue the show frame-relay lmi vty 0 4 command