a) What type of modulation is this? b) If the transmitted bit rate is 9600 b/s, what will be the baud rate using this modem?

a) What type of modulation is this?b) If the transmitted bit rate is 9600 b/s, what will be the baud rate using this modem?c) Suppose that a fallback mode at 4800 b/s, with the same baud rate, is required. Draw a constellation diagram showing how this could be accomplished. (There is more than one right answer.)d) When would a fallback mode of operation be useful?