A host is to become part of a hierarchical naming topology.  Which of the following services are required？（）

单项选择题ToaddaTTYTerminaltoSerialport1，whichofthefollowingsetofoptionsshouldbechosen？（）

A.tty rs232 Asynchronous Terminal then sa1 Available 01-S2 Standard I/O Serial Port
B.tty rs422 Asynchronous Terminal then sa1 Available 01-S2 Standard I/O Serial Port
C.tty rs232 Asynchronous Terminal then sa0 Available 01-S1 Standard I/O Serial Port
D.tty rs422 Asynchronous Terminal then sa0 Available 01-S1 Standard I/O Serial Port

单项选择题Whichcommandcanbeusedtomodifynetworkoptions？（）

A.netstat
B.ifconfig
C.chdev
D.no

单项选择题AllofthefollowingsettingswillresultinagettyprocessontheconfiguredportEXCEPT：（）

A.Enable
B.Disable
C.Share
D.Delay

单项选择题WhichcommandcanbeusedtoverifyallthefilesystemsthatareexportedbyanNFSserver？（）

A.showmount -e hostname
B.showmount -d hostname
C.showmount -a hostname
D.showmount

单项选择题NFSisexperiencingnameserviceresolutiondifficulties.WhichcommandreportstheLEASTusefulinformationintrouble-shootingthisproblem？（）

A.nfsstat -s
B.lssrc -s named
C.ls -l /etc/resolv.conf
D.nslookup hostname