What does it mean for a wireless LAN device to be Wi-Fi certified?

A.
The hardware has been verified to avoid interference with cordless phones, microwave ovens, and other similar interfering devices.

B.
The hardware has been verified to operate within the 802.11a/b/g standards.

C.
The hardware has been verified to work with home stereo systems and musical instruments.

D.
The hardware has been interoperability tested with other 802.11a/b/g compliant hardware.