单项选择题WhenplanningforvoicedeploymentswiththeCiscoUnifiedWirelessIPPhone7921GhandsetinamultifloorbuildingwithaWLANthatoperatesatan11MB sdatarate,howmanydecibelsreferencedto1milliwattofsame-channelseparationarerecommendedbetweenfloors?()
A.13 dBm
B.19 dBm
C.25 dBm
D.31 dBm