In amplitude modulation, when Ec is the amplitude of carrier wave and the modulation factor is 1, them the amplitudes of USB and LSB are ___________.
`E_c/2,E_c/2`
`E_c/2,(-E_c)/2`
`(-E_c)/2,E_c/2`
`E_c/2,(3E_c)/2`
why option c is wrong