ANS:C - 0.8–2 volts

The voltage range for the binary signal are:

0 to 0.8 >> Low >> Logic 0 An output voltage 0.8 volts or less is considered to be logic "0".

0.8 to 2 >> invalid Voltages between 0.8 volts and 2.0 volts are considered invalid (illegal).

2 to 3.5 >> High >> Logic 1 When digital logic has an output voltage of two volts or above its output is Considered to be logic "1'.