In which layer of the TCPnP layers are emaA programs mainly used? Application layer Host-to-host, or transport layer intemet layer Network access layer Physical layer QUESTION 17 A communication channel has a bandwidth of 1 MHz , and a signal-to-noise ratio of 255 . What is its channel capacity? A. 8Mbps B. 4 Mbps C.2Mbps D. 6Mbps E. None F. 10Mbps .