单项选择题

A.InboundpacketsarepermittedonlyiftheyarepartofalegitimatedataflowinitiatedbyadeviceontheTeleworkerhomenetwork.
B.Allpacketsarecheckedforintegritybyanalyzingtheirchecksum.
C.EverypacketischeckedtoseeifitwassentthroughtheVPNtunnel.
D.EverypacketisinspectedtoseeifanydisallowedURLsareincluded.URLsareforwardedtothesecuritycacheengineforauthorization.