The message signal m(t) = 2cos(400t) + 4sin(500tπ/3) modulates the carrier signal c(t) = acos(8000πt). What is the modulated signal?
a) 2cos(400t)cos(8000πt) + 4sin(500tπ/3)cos(8000πt)
b) 2cos(4800πt) + 4sin(500tπ/3)cos(8000πt)
c) 2cos(8400πt) + 4sin(500tπ/3)cos(8000πt)
d) 2cos(400t) + 4sin(500tπ/3)sin(8000πt)