paul executed the show interfaces command and reviewed the output. which output indicates a layer 2 problem with the serial0/1/1 interface? serial0/1/1 is up, line protocol is down. serial0/1/1 is up, line protocol is up, but ping fails. serial0/1/1 is up, line protocol is up, ping succeeds, but a telnet connection can't be established. serial0/1/1 is down, line protocol is down. serial0/1/1 is administratively down, line protocol is down.