Digital signals are discrete and typically represented by these two values.

• A. 0 and 1
• B. 0 and -1
• C. A and B
• D. True and False

Answer: (A)

Digital signals are two-level, discrete representations used to encode information. In practice, this means information is carried by two distinct states, typically shown as 0 and 1. This binary scheme aligns with how digital circuits are built: transistors switch between a low and a high voltage, creating clearly separable levels that the logic circuits can reliably interpret. The simplicity of using two states makes boolean logic straightforward, robust against noise, and easy to implement with reliable threshold detection.

Other options don’t fit as the standard hardware representation. A value like -1 is not a typical binary level in digital electronics, where a clear low or high (often 0 or 1) is preferred. The idea of using A and B is just symbolic labels, not actual numerical levels. True and False are logical concepts that map to 1 and 0 in software, but the hardware itself uses 0 and 1 as the fundamental levels.