A modulated signal Cm(t)=30sin300πt+10(cos200πt−cos400πt) . The carrier frequency fc , the modulating frequency (message frequency) fm and the modulation index μ are respectively given by :
a. fc=200 Hz; fm=50 Hz; μ=21
b. fc=150 Hz; fm=50 Hz; μ=32
c. fc=150 Hz; fm=30 Hz; μ=31
d. fc=200 Hz; fm=30 Hz; μ=21