The technique used to transmit audio signals in television broadcasts is Frequency Modulation (Option 2). This is due to the fact that FM is less susceptible to signal interference, providing a clear and high quality audio.

Option 1, Amplitude Modulation, is not typically used for audio in television broadcasts because it is more prone to noise interference.

Option 3, Pulse Code Modulation, is a method used to digitally represent sampled analog signals, but it is not the primary method used for transmitting audio in TV broadcasts.

Option 4, Time Division Multiplexing, is a technique that can be used in data communication for sharing a communication medium by dividing it into multiple channels based on time, but again, it`s not commonly used for transmitting audio signals in television broadcasts.

So, FM (Frequency Modulation) stands as the correct answer because of its benefits in transmitting clear and high quality audio signals in TV broadcasts.