How should the network administrator configure the serial interface of the main office router to make the connection?

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:
Cisco High-Level Data Link Controller (HDLC) is the Cisco proprietary protocol for
sending data over synchronous serial links using HDLC. So HDLC runs only in Cisco router. PPP
is not proprietary protocol it’s a open source every cisco router and non-cisco router understand
the PPP protocol.So we need to configure the PPP protocol if connection is between cisco and
non-cisco router.