A network administrator needs to configure a serial link between the main office and a remote
location. The router at the remote office is a non-Cisco router. How should the network
administrator configure the serial interface of the main office router to make the connection?

A.
Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# no shut

B.
Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation ppp
Main(config-if)# no shut

C.
Main(config)# interface serial 0/0
Main(config-if)# ip address 172.16.1.1 255.255.255.252
Main(config-if)# encapsulation frame-relay
Main(config-if)# authentication chap
Main(config-if)# no shut

D.
Main(config)# interface serial 0/0
Main(config-if)#ip address 172.16.1.1 255.255.255.252
Main(config-if)#encapsulation ietf
Main(config-if)# no shut

Explanation:
With serial point to point links there are two options for the encapsulation. The default, HDLC, is
Cisco proprietary and works only with other Cisco routers. The other option is PPP which is
standards based and supported by all vendors.