Which modulation technique is commonly used in AM broadcasting?

Amplitude Modulation is the correct answer because it is the primary technique used for AM broadcasting. In amplitude modulation, the amplitude of the carrier wave is varied in proportion to the waveform being sent, which typically contains audio signals such as music or voice. This allows the transmitted signal to carry information, and the varying amplitude can be detected by a receiver tuned to the appropriate frequency.

In the context of AM broadcasting, the receiver demodulates the amplitude variations to reproduce the original audio signal. This form of modulation is well-suited for radio waves and has been used extensively since the early days of radio transmission, making it an integral part of traditional broadcasting systems.

The other modulation techniques mentioned, such as Frequency Modulation, Phase Modulation, and Pulse Modulation, serve different purposes and are used in various applications, but they do not represent the standard method of modulation for AM broadcasting. Frequency modulation, for instance, varies the frequency of the carrier instead of the amplitude and is used in FM radio broadcasting.