YournetworkconsistsofasingleActiveDirectorydomain.AllserversrunWindowsServer2003ServicePack2(SP2).AfirewallseparatestheinternalnetworkfromtheInternet.ThefirewallblocksalloutboundtrafficexceptforHTTPandSMTPtraffic.YouinstallaDNSserver.TheDNSserverisconfiguredtousethedefaultroothints.YouneedtoensurethattheDNSservercanresolvethehostnamesontheInternet.Whichportshouldyouopenonthefirewall?()
A.53
B.135
C.500
D.3389