A male voice after modulation-transmission sounds like that of a female to the receiver. The problem is due to
(a) poor selection of modulation index (selected 0 < m < 1)
(b) poor bandwidth selection of amplifiers
(c) poor selection of carrier frequency
(d) loss of energy in transmission
When the selection of bandwidth for transmission is improper, the frequency of the modulated signal becomes more though the male voice frequency is less than female; thus, the voice sounds feminine. Therefore, the answer is (b) poor bandwidth selection of amplifiers