R1# sh ip int br Interface IP-Address OK? Method Status Protocol FastEthernet0/0 172.16.1.1 YES manual up up Serial0/0 10.1.1.1 YES manual up down Serial0/1 unassigned YES NVRAM administratively down down

Hosts with ip address 172.16.1.10 are unable to reach hosts in network 192.168.1.0/24. Based on the output from R1, what are two possible reasons for the failure?

A.	The cable that is connected to serial0/0 on R1 is broken.
B.	Interface S0/0 on R2 is administratively down.
C.	Interface S0/0 on R1 is configured with an incorrect subnet mask.
D.	The IP address that is configured on S0/0 of R2 is not in the correct subnet.
E.	Interface S0/0 on R1 is not receiving a clock signal from the CSU/DSU.
F.	The encapsulation that is configured on S0/0 of R2 does not match the encapsulation that is configured on S0/0 of R1.