单项选择题
A.en0
B.lo0
C.tr0
D.ping results in "Sendto：Network is unreachable" message
单项选择题 InaTCP/IPnetwork，whichofthefollowingcommandsutilizestheICMPprotocol？（）
单项选择题 Anadapterstatedoesnotshowavailableafterareboot.Whichofthefollowingisthemostprobablecause？（）
单项选择题 Ahostistobepartofaverysmallprivatenetwork，whichwillneverbeconnectedtoanyothernetworks.Whichofthefollowingnameresolutionschemeswouldbetheeasiesttoimplement？（）
