Which design element is a best practice when deploying an 802.11b wireless infrastructure?

Which design element is a best practice when deploying an 802.11b wireless infrastructure?
A . disabling TPC so that access points can negotiate signal levels with their attached wireless devices.
B . setting the maximum data rate to 54 Mbps on the Cisco Wireless LAN Controller
C . allocating non overlapping channels to access points that are in close physical proximity to one another
D . configuring access points to provide clients with a maximum of 5 Mbps

Answer: C