单项选择题
A.Class A
B.Class B
C.Class C
D.Class D
单项选择题 Whichofthefollowingadaptersshouldbeconnectedtocoaxialcablingwithouttheuseofmediaconverters？（）
单项选择题 Whichofthefollowingclassnetworksrepresentsapossibilityofbeingfurthersubnettedinto2subnetsof128hostspersubnet？（）
单项选择题 WhichofthefollowingClassAnetworksisreservedfor"privatenetworks"useonly？（）