How does 802.11h (DFS) help 802.11 devices avoid interference?

A.
The standard enables 802.11n APs to switch channels when they encounter any interference
on any channel in the 5.0 GHz range. It offers no benefits for non-n devices.

B.
The standard ensures that 802.11 devices do not interfere with other non-802.11 devices that
use the 2.4 GHz range.

C.
The standard ensures that 802.11 devices operating in the 5 GHz (UNII2-UNII2e) frequency
range do not interfere with radar.

D.
The standard enables 802.11g and 802.11n devices to switch channels when interference
causes the SNR to drop below the minimum level.