What statement is true concerning the use of Orthogonal Frequency Division Multiplexing (OFDM) modulation method in IEEE 802.11 WLANs?
A . OFDM was used by Frequency Hopping Spread Spectrum (FHSS) PHY devices.
B . OFDM was first introduced in 802.11 and is used by the ERP, HT and VHT PHYs as well.
C . OFDM implement BPSK modulation to allow for data rates up to 7 Gbps.
D . OFDM modulation is used only in 5 GHz 802.11 transmissions.
Answer: D
Explanation:
Reference http://www.rhyshaden.com/802_11a.htm