About QPSK, the incorrect statement isa. The SER performance of QPSK in an ideal AWGN channel is equal to that of BPSKb. Each QPSK symbol corresponds to two bits.c. The spectrum efficiency of QPSK is 2 bps/Hz.d. The BER performance of QPSK in an ideal AWGN channel is identical to that of BPSK.