What is DTX or Discontinuous Transmission in a GSM network?

• A. DTC stops transmitter when the person is not talking. So less number of voice signals reach BTS with less noise.
• B. With the help of VAD (Voice Activity Detection), mobile identifies conversation and noise to turn off transmission.
• C. On the opposite end, the receiver produces a noise called Comfort Noise. With out this, DTX makes the opposite person think that the line or call is cut.
• D. All