What features were introduced in the IEEE 802.11h amendment in order to uphold regulatory requirements for 5 GHz operation? (Choose 2)
A. 256-QAM
B. Distributed Coordination Function (DCF)
C. Phase Shift Keying (PSK)
D. Transmit Power Control (TPC)
E. Radio Resource Management (RRM)
F. Dynamic Frequency Selection (DFS)