CCNA题库中的一道题,求详解,求大腿啊.Refer to the exhibit.Witch WAN protocol is being used?A. ATMB. HDLCC. Frame RelayD. PPP

CCNA题库中的一道题,求详解,求大腿啊.Refer to the exhibit.Witch WAN protocol is being used?A. ATMB. HDLCC. Frame RelayD. PPP
CCNA题库中的一道题,求详解,求大腿啊.
Refer to the exhibit.Witch WAN protocol is being used?
A.  ATM
B.  HDLC
C.  Frame Relay
D.  PPP

CCNA题库中的一道题,求详解,求大腿啊.Refer to the exhibit.Witch WAN protocol is being used?A. ATMB. HDLCC. Frame RelayD. PPP
我在图中唯一看到的就是LMI及DTE（一般电信端为DCE）：
本地管理接口（LMI）
LMI是指路由器与电信的局端Frame-Relay交换机之间通信的协议,负责管理设备之间的连接以及维护连接状态.
所以选Frame-Relya
顺带发我SHOW出的信息：
Serial1/2 is administratively down, line protocol is down
Hardware is M4T
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation FRAME-RELAY, crc 16, loopback not set
Keepalive set (10 sec)
Restart-Delay is 0 secs
LMI enq sent 0, LMI stat recvd 0, LMI upd recvd 0, DTE LMI down
LMI enq recvd 0, LMI stat sent 0, LMI upd sent 0
LMI DLCI 1023 LMI type is CISCO frame relay DTE
FR SVC disabled, LAPF state down
Broadcast queue 0/64, broadcasts sent/dropped 0/0, interface broadcasts 0
Last input never, output never, output hang never
Last clearing of "show interface" counters 00:00:06
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/0/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1158 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up Last input never, output never, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/1000/64/0 (size/max total/threshold/drops)
Conversations 0/0/256 (active/max active/max total)
Reserved Conversations 0/0 (allocated/max allocated)
Available Bandwidth 1158 kilobits/sec
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
0 packets output, 0 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
1 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up