84J3 D
 In an AM broadcast signal using voice:
A. Varying the amplitude of the carrier and employing both sidebands without the carrier.
B. Varying only the amplitude of the carrier, depending on Double or Single-Sideband operations.
C. Varying the amplitude of the carrier and employing both sidebands and the carrier.
D. There is a carrier with constant amplitude and frequency with complex upper and lower sidebands varying in amplitude and frequency.
