单项选择题YouworkastheenterpriseexchangeadministratoratXxx.TheXxxnetworkconsistsofadomainnamedxxx.XxxisusingMicrosoftExchangeServer2010astheirmessagingsolution.YouhavetohavetheApplicationIdentifierofxxxstoredinaDNSrecord.TheApplicationIdentifierisusedforthefederatedtrust.WhatactionsmustyoutakeontheDNS?()
A.You must set up recipient filtering.
B.You must set up a Host (A).
C.You must use a TXT record.
D.You must use a Pointer (PTR) record.
E.You must use a Mail exchange (MX) record.