What is the command sequence to configure an FXS port as a signal loop-start?
A. router(config)# voice-port slot/port
router(config-voiceport)# signal loopstart
router(config-voiceport)# shutdown
router(config-voiceport)# no shutdown
B. router(config)# voice-port slot/port
router(config-voiceport)# signal loopstart
C. router(config)# voice-port slot/port
router(config-voiceport)# signal groundstart
router(config-voiceport)# shutdown
router(config-voiceport)# no shutdown
D. router(config)# voice-port slot/port
router(config-voiceport)# signal groundstart
