When compared with legacy Power Save mode, how does VHT TXOP power save improve battery life for devices on a WLAN?
A . VHT TXOP power save allows stations to enter sleep mode and legacy Power Save does not.
B . VHT TXOP power save uses the partial AID in the preamble to allow clients to identify frames targeted for them.
C . Legacy Power Save mode was removed in the 802.11ac amendment.
D . VHT TXOP power save allows the WLAN transceiver to disable more components when in a low powerstate.