单项选择题AcmeCompanyhasseveralofficesaroundthecountry.ThecompanyhasdeployedaVoIPnetworkwithCiscoUnifiedCallManagerinamultisitecentralizedconfigurationbutthereisarequirementtoplaceacallagentatsomeoftheremotesites.WhichIOSgatewayfeatureshouldbedeployedattheremotesitetoenablelocalcallcontrol?()
A. Gatekeeper multizone
B. Call Admission Control (CAC)
C. Automatic Alternate Routing (AAR)
D. Survivable Remote Site Telephony (SRST)
E. Cisco Unified CallManager Express (CME)