Which one of these options best describes the ideal WLAN design for wireless VoIP clients?

Which one of these options best describes the ideal WLAN design for wireless VoIP clients?

A.
smaller cells with all configurable speeds to ensure that all clients (802.11a/b/g) can associate to the wireless infrastructure

B.
smaller cells with higher speeds and CAC-enabled prioritization of WMM clients

C.
larger cells with higher speeds and WPA2 security enabled to ensure the best possible coverage

D.
smaller cells with APs in the inner areas using omnidirectional antennas, and APs on the outer walls using directional antennas facing inward