The correct answer is (b). Pulse Code Modulation (PCM) is a technique used to transmit audio signals in television broadcasts. It works by converting the audio signal into a series of pulses, which are then transmitted over the air. The receiver then converts the pulses back into the original audio signal.
Amplitude modulation (AM) is a technique that is used to transmit audio signals by varying the amplitude of a carrier wave. This means that the amplitude of the carrier wave is increased and decreased in accordance with the amplitude of the audio signal.
Frequency modulation (FM) is a technique that is used to transmit audio signals by varying the frequency of a carrier wave. This means that the frequency of the carrier wave is increased and decreased in accordance with the amplitude of the audio signal.
Time division multiplexing (TDM) is a technique that is used to transmit multiple signals over a single channel by dividing the channel into time slots. Each signal is then transmitted in its own time slot.
PCM is a more efficient technique than AM or FM, and it produces a higher quality signal. This is why it is the preferred technique for transmitting audio signals in television broadcasts.